I laugh at you for saying the armor is crap. If you take the time to increase your smithing skill and put points into the arcane smith perk you can upgrade the armor to legendary. it's a pretty good set of armor. I'm at level 42 in the game and still wearing it. I am not wearing anything else. The perks for lock picking, pick pocketing, extra pockets from the chest piece, and the better prices from the cowl are all worth keeping it on. I don't wear anything else. Don't need anything else.
It's not a bug, just you see it that way. Also I'm not blindly defending bethesda. This is my first game from Bethesda actually that I've played this long. I tried Oblivion on a friends recommendation, I hated it and returned it the next day. I haven't returned this game yet. But no I'm not blindly defending Bethesda. I'm stating that this isn't a bug, completely different thing here.
I say it's crap because that's my opinion. Don't hijack this into an armor effectiveness debate.
In case people need reminding, THIS IS AN ELDER SCROLLS GAME. I can go wherever I want and play how I see fit.
That being said, to me, that armor is crap. I just forged Dragon Scale light armor and enchanted it myself (and it's legendary) so yes, I thought the thieves guild armor was crap. I needed the coin, it was weight, and I made an honest mistake. Is that what you would have done? Maybe. Maybe not.
BUT WHO CARES.
The whole point is that the Thieves Guild armor is essential, and in a free-for-all game like the Elder Scrolls series, you would think that there would be a balanced fail-safe like there are for other essential quest items. I also used the phrase "Ad Hominem" in regards to not addressing the issue, but the player. Logic: your friend.
Bug, glitch, bad planning, I'm not going to split hairs with anyone about what this is.... but understand that this is BAD, and there really isn't an argument anyone can come up with that logically tells anyone otherwise. Never mind the fact that:
1) Unable to finish.
2) Unable to have ANY dialogue with the woman (or use her as a fence) as she will be indefinitely stuck at the "where's your armor" dialogue.
3) There's no other way to get it, even by killing other members.
4) Every other quest item so far restricts you from removing it from your inventory, making this a "balance" issue of sorts.
This needs to be addressed in a patch, bottom line, end of debate.