Yeah, my first build was a stealth character, I did it just fine. You're mostly likely specing your builds wrong for stealth or wearing a million pounds of armor clanking around thinking you're being stealthy. There's specific armor pieces meant for stealth, which also help a ton.

The weapon modding isn't broken. If you find a gun with a suppressor, you can take that off and put it on the same model as yours. I don't think needing a skill/crafting to make a whole suppressor warrants the game being called broken.