As long as you have proficiency in the armor in question, you're fine to wear it.
That said, while an armored wizard/sorcerer is theoretically possible (relatively easy for githyanki and one of the dwarf subraces), it's generally more trouble than its worth to reach that point. I've built that a couple of times just because it's a fun concept, but you can get the same ACs using spells and magic items. Which eats up attunement slots. In the end, your best defense remains getting other players to tank for you.
From a practical standpoint, you're unlike to get higher than Medium Armor, by the way. The Heavy Armors all have Strength requirements or you suffer penalties.
I suppose you COULD have enough strength to pull it off....if you planned to do armor anyway....you wouldn't need the Dex....but, eh....
It's cool, but in the long run it doesn't affect a wizard's effectiveness too much.
Last edited by Thrythlind; 22/10/20 11:37 PM.
I didn't even think about the gith having armor proficiencies but when I was shopping with one of the vendors and moused over a chain shirt, I noticed it didn't tell me I couldn't wear it. So I got to thinking, why am I wearing this stupid padded armor when I could get the chain shirt and then I remembered the arcane spell failure stuff. That got me looking on the web to see if that was still a thing in 5e. 
