Already OR/AS is looking leagues better than X/Y. I'm excited for this!
e: About Slaking-
That Pokemon was designed for a time when the stupid power creep that happened around Gen 5 wasn't an issue. Back then, having 150 HP, 160 Attack, and 100 Def all in one package for a non-legendary Poke was... Godly. Not to mention, it had a better movepool in gen 3, because typing wasn't dependent on the moves themselves, but their element type. Slaking can use SHADOW BALL (Ghost was a physical type, so it was viable), and lets not forget that good fighting moves didn't really come into fruition until Gen 4. Without some hindrance, counterplaying that monster would have been immensely difficult, considering it's both tanky as balls for the power level of Pokemon back then and it hits like a truck. Heck, even with truant, that thing was still a pain in the ass to deal with for Norman's gym, just imagine if it didn't have truant.
The problem here, obviously, is that it hasn't aged well. We now have close combat and iron fist Conkeldurrs to faceroll any normal type, and Mega evolutions, in their insta-win cannon nature, completely undermine anything Slaking stands for. The redefining of physical/special moves also gave it a bit of a blow, since it has to resort to stuff like Shadow Claw and Night Slash, both having a mediocre base power, to deal with ghost types. It doesn't even get Payback. So yeah... That's at least what I can deduce as to why Slaking is the way it is.
Archeops is in a better position by comparison. At least when given the chance and addressing its chief counters through good team-building, there is arguably nothing that'll stop it from sweeping entire teams. I know this, because I've been one of its victims at one point. X_X