whelp, that's your opinion - a valid one for sure, but let me bring the polar opposite to the table, just for balance (and also because it's my own honest opinion and experience).
The guns (150mm) are great if handled right. Sure, their DPM isnt amazing, but they give you a mean alpha punch - use them accordingly whenever possible (as in, fade in, fade out - avoid DPM races where you can). And their AP is a sight to behold - ever smoked up 7km from an oblivious Omaha or Pensacola and given him a 15k quad citadel salvo? I have, and it's hella fun when it happens :D Plus, they hurt BB broadsides quite a lot with AP, or provide pretty reliable fires with HE.
And don't forget, you've got a ridiculously hefty HP pool for a T6 DD - only Gnevny comes somewhat close, and there are only two DDs that you can even possibly meet in your tier range that have more base health than you: the Maass and the Z23. Even a freaking Kiev has less base health than you. That gives you a lot of buffer to fight other DDs with.
The torps are pretty decent for their tier. Sure, they dont quite match up to the IJN counterparts, but you can easily stealthtorp with CE, you'Ve got a decent reload on them, and the damage doesnt feel quite as anaemic yet :)
Concealment is also not horrible (again assuming you have CE). Sure, 6.6km ain't great, but it's not disastrous - you'll outspot plenty of equal tier DDs that dont have CE yet, and arent miles behind most other T6 and T7 DDs (meeting a Benson or some such does stink tho...).
Maneuverability I'll give you isnt good, but you do have hydro for torp dodging at least.
Speed is pretty much the same as everything else at your tier except the Gnevny which is a little faster.
Smokes are german, yes - so play accordingly. You're not a good smoke-and-spam boat, so dont try to be one.
BB AP didnt feel more dangerous than in other DDs to me in the Gaede (yet - it's definitely noticable later on in the line), but that's purely subjective experience.
The Hydro can be a ridiculously effective tool if used right. Remember, a DD that smoked up cant see you coming - so that often provides opportunities to be cheeky. And it makes you mostly immune to surprise/random torps while it's running - developing a feeling for when to use it is very helpful here... oh, and when you have to smoke up and someone (say, a Battleship) rushes you, it's also a total lifesaver to see them coming at double the distance that you otherwise would.
For me, the Gaede is easily the best and most fun T6 DD overall - an absolute keeper because it's decent to good at everything and has a unique tool in its Hydro.