Sorcerer/Paladin, where to go from there?

[Vanguardian]

I'm playing a Half-Elf lvl 6 Vengeance Paladin/lvl 5 Favored Soul Sorcerer with the War domain.
My stats are Str 8 Dex 16 Con 14 Int 10 Wis 10 Cha 18 and I have the Warcaster feat.
I use medium armor, since my sorcerer level was taken first and I wanted more swashbuckling feel for my character.
My skills are Stealth, Persuasion, Deception, Survival, Acrobatics and Arcana.
My spells known from the sorcerer side are Shield, Disguise Self, Mirror Image, Enhance Ability, Detect Thoughts, Haste, as well as Shield of Faith, Spiritual Weapon and Spirit Guardians from my domain that I use frequently. My most used cantrips are Green-Flame Blade, Lightning Lure and Mage Hand.
My metamagic choices are twin spell and subtle spell.
From the paladin side I usually prepare Cure Wounds, Protection from Good and Evil, Command, Zone of Truth, Aid, and Find Steed, as well as Hunter's Mark, Misty Step and Hold Person from my Oath.
I use the defense combat style, rapier and a shield putting my AC in the heavy armor category.
I have the Inheritor background with my inheritance being a dragonmark of storm although it has no mechanical benefits to back it up (but my character aims for more stormy feel).

I am in a party with a warforged rogue thief and valor bard, and a wildhunt shifter archer hunter ranger. In a combat against significant threats I usually use a twinned haste on the ranger and the rogue, while using a spiritual weapon myself with occasional Spirit Guardians if we are faced with a mob of low level enemies. Since we don't have a healer I usually start the day with an aid spell with my highest spell slot on the melee characters. I also employ the shield spell and mirror image to keep myself from having to make too much concentration checks a in combination with warcaster, aura of protection and con save proficiency - my haste or spirit guardians spell manages to make it through the combat uninterrupted. Cure Wounds and Protection from Good and Evil are used only in a case of specific emergency and the remaining spells are used mostly for out of combat purposes.

As a whole it is enjoyable ride so far and I am very happy with the character, but I am not sure where to go from here. I probably want to go for Paladin 8/Sorcerer 8 in order to optimize my feat/ability scores progression (since I have two main stats to rise). From there on I am not sure. The paladin side does not seem overly attractive... I get Improved Divine Smite and Aura of Courage. Improved Divine Smite is cute I guess, but comes a bit late. Although it helps a ton against opponents resistant to my Green-Flame Blade and is overall slight dps increase vs. isolated enemies when green-flame cleave effect is wasted.
On the sorcerer side though... I can find a single spell past lvl 4 that I like... Control Weather is thematic for the character but seems pretty bad, there are a ton of somewhat decent concentration effects, but I will usually be concentrating on a twinned haste. Am I missing something or there are no decent sorcerer spells in the 5-8 level range that are decent for a melee sorcerer? Reverse Gravity is nice provided enemies cant fly and that's about it... more slots for preparing spiritual weapon and smites I guess... are there some decent spells that are avoiding my attention? Creation seems very limited, the Investures are nice but require concentration. Amimate Objects maybe, but it will drag down combat immensely with a lot of rolls, so... pass. What would you choose in my shoes and why?

[bid]

I'm playing a Half-Elf lvl 6 Vengeance Paladin/lvl 5 Favored Soul Sorcerer with the War domain.
My stats are Str 8 Dex 16 Con 14 Int 10 Wis 10 Cha 18 and I have the Warcaster feat.
You need Str13 to MC in/out of paladin.

Aside from this technicality, you want paladin 9 to have access to all its 3rd spells. Your sorcerer side is stuck with whatever spells you know, but your paladin side can change prepared spells every day.

You can get some 6th spells if you reach sorcerer 11, see if any of those is worth more than IDS.

[Gtdead]

I'd reach Sorcerer 7 for polymorph/banish/greater invi and then go back to paladin. Also since you DM allows UA stuff, one dip to Undying Light warlock may help you. You get to add more damage to your fire/radiant spells, this means GFB too. You also get access to Sacred Flame. Or you can get 3 and grab Tome, adding Charisma Shillelagh to your list (especially if you don't want to get more sorcerer levels). Undying Light Warlock fits thematically to your character's concept.

I'm planning to use this on my Paladin2/Drac Sorcerer x build. I thought that having a radiant attack which targets DEX save on a character that has natural flight, who can quicken it, and can wish for a copy of himself, throwing around 4 sacred flames per turn, is a potent build. Also my firebolt gets double cha modifier added to his damage.

Also you may want to grab Medium Armor Master, you already have the DEX for it, you have invested in stealth, so why not? Personally I think that AC is the best possible thing you can increase as a melee character. I would do that without a second thought.

[Gastronomie]

Paladin is fine at 6, Aura of Protection is hands down the strongest ability Paladins ever get in their entire career. Going past that is not a good idea, at least in my opinion (unless your Level 7 oath ability is a really, really good one - such as an Oathbreaker in a party with a necromancer).

The whole point of going a lot of levels Sorcerer is not just the spells, it's also the Sorcerery Points. Quickened Spell is absolutely nuts in a Paladin/Sorc build - you want to let it off as much as possible.

As aforementioned by others, Warlock is another good option. Either Fiend (increases your tankiness) or Undying Light (increases your abilities as a striker).

TBH the best Sorcerery Origin for a PaladinSorc is prolly either Draconic or Shadow, but well, NVM. It's cause the Favored Soul Sorcerer's level 6 ability overlaps the Paladin's, but well, not like it's a bad option, and besides, whatever's most fun for you is always the best.