I am sure that this is not the first attempt at a shapeshifter class, or the last, but never the less I would like to hear some opinions on how the balance looks. I have a feeling that it is over powered, then again I have the same feeling about just about everything I homebrew. The concept is based off of some old 3.5 material.

Spoiler: Table
Level Proficency Bite/Slam Claw/Talon Features
1 +2 1d6 2d4 Shapeshift, redator Form
2 +2 1d6 2d4 Combat Recovery
3 +2 1d6 2d4 Vermon Form
4 +2 1d6 2d4 Ability Score Improvement
5 +3 1d6 2d4 Aquatic Form
6 +3 1d8 2d6 Primal Strike
7 +3 1d8 2d6 Aerial Form
8 +3 1d8 2d6 Ability Score Improvement
9 +4 1d8 2d6 Ferocious Slayer Form
10 +4 1d8 2d6 -
11 +4 1d10 2d8 Elemental Fury Form
12 +4 1d10 2d8 Ability Score Improvement
13 +5 1d10 2d8 Forest Avenger Form
14 +5 1d10 2d8 Voice of the Beast
15 +5 1d10 2d8 Thousand Forms
16 +5 1d12 2d10 Ability Score Improvement
17 +6 1d12 2d10 Beast Spells
18 +6 1d12 2d10 -
19 +6 1d12 2d10 Ability Score Improvement
20 +6 1d12 2d10 Primal Champion

Spoiler: HP/Proficiencies/Equipment
Hit Points
Hit Dice: 1d10 per level
Hit Points at 1st Level: 10 + your Constitution modifier
Hit Points at Higher Levels: 1d10 (or 6) + your Constitution modifier per level after 1st

Armor: Light armor, medium armor, shields
Weapons: Simple weapons, martial weapons
Tools: None
Saving Throws: Strength, Dexterity
Skills: Choose three from Animal Handling, Athletics, Insight, Investigation, Nature, Perception, Stealth, and Survival

You start with the following equipment, in addition to the equipment granted by your background:
(a) scalemail or (b) leather armor
(a) two short swords or (b) two simple melee weapons
(a) a dungeoneer's pack or (b) an explorer's pack
A longbow and a quiver of 20 arrows

Spoiler: Shapeshift
You can shapeshift at will into powerful animal or nature-oriented forms. Each time you use this ability, you can choose the exact look that your shapeshifted form takes. Shifters pick animals from the terrain and climate they're most familiar with. For example, a shifter from a jungle might adopt the form of a black panther when in predator form, while one from the taiga might shapeshift into a white wolf. The two forms look different, but functionally they are identical.

Shifting is a bonus action and does not provoke an attack of opportunity. If you are capable of taking more than one form, you can shapeshift directly between two forms without returning to your normal form. There is no limit to the number of times per day you can change forms, nor to the amount of time you can spend in a shapeshifted form. You retain your normal Hit Dice, hit points, ability scores, attack bonuses, saving throw bonuses, and skills regardless of your form. You keep all special attacks and qualities of your normal form, except for those requiring a body part your new form does not have.

You cannot cast spells, and your ability to speak or take any action that requires hands is limited to the capabilities of your beast form. Shifting does not break your concentration on a spell you have already cast, or prevent you from taking actions that are part of a spell, such as ensnaring strike, that you've already cast.

You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so. You gain darkvision with a range of 30 feet while shifted. If you already have darkvision, the range of your darkvision is increased by 30 feet.

You choose whether your equipment falls to the ground in your space, merges into your new form, or is worn by it. Worn equipment functions as normal, but the DM decides whether it is practical for the new form to wear a piece of equipment, based on the creature's shape and size. Your equipment does not change size or shape to match the new form, and any equipment that the new form cannot wear must either fall to the ground or merge with it. Equipment that merges with the form has no effect until you leave the form.

Unless otherwise noted in the descriptions below, you retain your size and space when you adopt a new form. You always retain your type and subtypes, regardless of the nature of the form assumed. You don't gain any special attacks or qualities while shapeshifted except as described below. When you shapeshift into a form other than your own, you gain natural weapons (and reach with those weapons) as described below. These natural weapons deal damage as noted in the table above, these values are for a medium size creature and should be adjusted accordingly if you change size. You can use Dexterity instead of Strength for the attack and damage rolls of your natural attacks when shifted.

While you are shifted and wearing no armor, your AC equals 10 + your Dexterity modifier + your Wisdom modifier.

Spoiler: Forms
Predator Form: This form, traditionally that of a wolf, panther, or other predatory animals, is the first one a shapeshifter learns. While in predator form, you gain multiattack bite plus trip and claws. Your base land speed becomes 50 feet. You gain advantage on Wisdom (Perception) checks that rely on hearing and smell.

Vermin Form: At 3nd level, you can shift into a tiny creature such as a rodent or insect. While in virmin form you gain a bite attack. Your size decreases to tiny, you gain a climb speed of 20 feet. While in this form you gain advantage on Wisdom (Perception) checks that rely on hearing and smell and Dexterity (Stealth) checks.

Aquatic Form: At 5th level, you can shift into an aquatic creatures such as a fish, whale, or seal. While in aquatic form, you gain a bite attack that deals damage as if you were one size category larger. You gain a swim speed of 40 feet and the capacity to breath underwater. You gain advantage on Wisdom (Perception) checks that rely on smell.

Aerial Form: At 7th level, you can shift into a flying creature. Traditionally resembling an eagle, vulture, or bat, the aerial form enables fast travel and the ability to soar out of harm's way. While in aerial form, you gain gain multiattack bite and talons. You gain a fly speed of 50 feet (good maneuverability). You gain advantage on Wisdom (Perception) checks that rely on vision.

Ferocious Slayer Form: At 9th level, you can shift into a large and fierce predatory form, such as a tiger, bear, or dire wolf. While in ferocious slayer form, you gain multiattack bite and claws. Your size increases by one category. Your base land speed becomes 40 feet. You gain advantage on Wisdom (Perception) checks that rely on smell.

Elemental Fury Form: At 11th level, you can shift into a form of air, earth, fire, or water (your choice each time you shapeshift). While in elemental fury form, you gain a slam attack and you can attack twice, instead of once, whenever you take the Attack action on your turn. You gain immunity to an energy type related to the element chosen (air = electricity, earth = acid, fire = fire, water = cold). You gain a special movement type or bonus: Air = Fly 60 feet (average), Earth = Burrow 30 feet, Fire = +30 feet base speed, Water = Swim 60 feet. You don't need to breathe while in elemental fury form. You have the reach of a tall creature of your size.

Forest Avenger Form: At 13th level, you can take the form of a massive plantlike creature, similar to a shambling mound or a treant. (Shapeshifters not native to forest terrains typically rename this form to fit their environment.) While in forest avenger form, you gain a slam attack plus grab and you can attack twice with the slam attack, instead of once, when you take the Attack action on your turn. Your size increases by one category and you have the reach of a tall creature of your size (5 feet for Medium, 10 feet for Large). Your base land speed becomes 20 feet. You gain rock throwing (100 ft) damage equal to slam, and damage reduction 5/slashing while in forest avenger form.

Spoiler: Features
Spellcasting: Spellcasting per Ranger.

Combat Recovery: At 2nd level while you are shifted, you can use a bonus action to expend one spell slot to regain 1d8 hit points per level of the spell slot expended.

Primal Strike: Starting at 6th level, your natural attacks count as magical for the purpose of overcoming resistance and immunity to non magical attacks and damage.

Voice of the Beast : At 14th level you may speak normally while shifted.

Thousand Forms: By 15th level, you have learned to use magic to alter your physical form in more subtle ways. You can cast the alter self spell at will.

Beast Spells: Beginning at 17th level, you can cast many of your spells in any shape you assume. You can perform the somatic and verbal components of a spell while shifted, but you are not able to provide material components.

Primal Champion: At 20th level, you embody the power of the wilds. While shifted your Strength or Dexterity and Constitution scores increase by 4. Your maximum for those scores is now 24.