It's likely there's gonna be higher ilvls, so rares might not be worth as much. Then again that's only for the really top end stuff, and even then it'll still be valuable, less so though. For the uniques, no one can tell. They generally stay constant or increase in price, unless they're directly nerfed, but that doesn't happen that often.
The new uniques won't necessarily be better overall. They'll be better for specific builds, because that's how uniques work. I'd be surprised if they added like a "stronger shav" or something. There isn't a need to add a unique that does the same thing as another, regardless of expansion, new act or what not. It defeats the purpose. They might add a unique chest that's better for low life ES builds but only for specific ones though, for example one that improves melee damage but reduces spell/ranged damage or whatever and happens to be better at the low life thing than Shav, but only for melee builds. That'd be an acceptable new unique, but it wouldn't reduce the value of Shav.
Besides that, I don't know, I don't play standard, in fact I mostly delete my chars on standard. I think I have some decent stuff in my stash, but decent is like self found first month of HC league decent, so it's garbage for SC really, I just figured if I made a char on standard one day I'd want my best items that got sent there to build upon. It's a nice way to welcome the patches and nerfs imo, I'm never attached to any specific character or build, because they only last as long as the leagues, and after that they might as well be gone. I just make something new based on what's available at that point and looks fun. I made SRS and Tornado Shot for the 1month cause I never played with either skill before(they weren't in the game last time I played), it was fun.
