Shapechanger feat - How balanced would it be?

[Greywander]

I'm working on some racial feats for a homebrew race, and I was considering a Shapechanger feat. Browsing through the Monster Manual, there seem to be a number of variations:
Many only allow the creature to change into a few specific forms. A few allow any creature of a specific type and size (e.g. medium humanoid).
All of them specifically state that the creature retains their own statistics, except speed and size.
Most specify that your equipment does not transform with you, vampire is the exception but only transforms equipment you are wearing, not equipment you are carrying.

My initial thought was to have you simply able to transform into any beast of CR 1 or less. Equipment you are wearing should probably transform with you. Keeping your own statistics is a bit problematic. It's not so bad for monsters, where the statistics are set by the game designers or DM and are largely static. A player could have any statistics, though. You could turn into an earthworm, keeping your own Strength score, for example. Even worse, "keeping your statistics" could be interpreted as keeping all of your class features, such as spellcasting.

How gamebreaking would this be? I'm beginning to think that Wild Shape would make a better basis for this ability, and that I should probably drop the CR cap down to 1/2 or 1/4. Another thought is that I could have the player choose three or so beasts when they gain the feat, and from then on they can only shapechange into those specific beasts.

[Belier]

If somebody would want to wild shape he'd better play a druid or a spell caster with polymorph and alter self. I would'nt consider a feat for such abilities that are tied to class and spells. Also if the shapechanger keeps his stats CR is a bit less of an issue but I'd still limit it to a list because some multiattacks or abilities would be too much at low level like crocodile attack + grapple and restrain at the same time.

To be honest, I think it is plainly wrong to use this as a feat but you could try a homebrew race that can shapechange or have a spell like ability that can be used once per day like drow casting darkness.

If the class has the ability, it keeps is stats and hp and assume only the form attacks and abilities. When it goes out of hp ot reverts and goes incounscious.

If the race use a spell casting ability to cast once per day for free it could be an alterself once per day or even a very limited polymorph spells but restricted to a very small list of low cr creatures.

In both case, i'd be carefull not to give them flying and things that have too powerfull abilities and attacks because it would be usable from level 1. Utility would thus be to consider, like burrow speed, darkvision, grapple, stealth, climb speed etc.