Conjure Arms

I'm was torn about this spell. On the one hand, it can easily end up as a more expensive version of shillelagh: 1st level spell slot, cast as an action. On the other hand, it enables so-called "gish" builds to an extent not seen outside the Hexblade Warlock. I was originally going to recommend changing the spell to only summoning weapons you're already proficient with, but actually the simple weapon limitation is what makes this spell work.

Ultimately, it's a spell that I can't find fault it but nonetheless worries me about inclusion in my games. I'd really like people to test this out and to that end, I have to vote it up.

I appreciate that and hope that there will be some play testing out side of my games. The idea for the spell came from when I was playing Skyrim and you could summon a sword or a different weapon. I saw that there wasn't really a spell for that. So I made this, and I am always looking for feedback or suggestions on change. I'm new to D&D let alone home brewing so i'm not the best at balancing things. But i'm always trying to learn and create interesting homebrew creations.

I half expected this to summon actual severed arms, based on all the other homebrew spells I've read so far. Why are meme spells upvoted so much but actual spells like this are left with only 3 upvotes? I don't understand.

Why would a wizard ever conjure anything except a light crossbow with this spell? I like the limitation to simple weapons (though a morningstar is not simple, fyi), but I would personally further limit the ranged options to a shortbow. I would also give the option to summon thrown weapons with a bonus action (ie, throw a spear and then resummon it as a BA). All in all, I would word the spell as such:

You summon a ghostly copy of any simple melee weapon or a shortbow with 20 arrows. While this spell lasts, you are considered proficient with the weapon and can use your spellcasting ability modifier, instead of Strength or Dexterity, for its attack and damage rolls. If you throw or drop the weapon, you can use a bonus action on your turn to teleport it instantly to your hand. When the spell ends, the weapon and any arrows disappear.

Does this spell include ranged weapons? If so, does the caster need to have the appropriate ammo equipped or does it generate its own ammo?

I made a whole custom class around this premise for the same reason you made this spell, Skyrim conjuration weapons. The class is called the Convoker and its main abilities are summoning ethereal versions of weapons that you are proficient with (You start with simple weapon proficiency and then gain certain martial ones based off a subclass) and theyre also a half caster with only conjuration spells.