It should go without saying that nobody has played gen VI, so nobody can comment on it.
To the existing gens - there has been a certain amount of power creep, no matter how enthusiastically some few might insist otherwise. It's not noticeable at the higher ends, since GF remains wisely careful about introducing notably overpowered pokemon, but it's obvious if one has actually played the fifth gen games and paid close attention to the stats individually and broadly.
First - stats are much more effectively distributed in this gen. I saw someone mention Gigalith earlier as a nominal example of a gen 5 pokemon with detrimentally poorly distributed stats, since its special defense is so notably low. The thing though is that Gigalith is the exception, rather than the rule. The rule in this gen, quite plainly, is balanced defensive stats paired most often with beneficially skewed offensive stats. I could fill up the rest of this post listing the pokemon in the Unova dex that have close to even and often exactly even defense and special defense - in fact, it's the ones that don't, like Gigalith, that are the exception. Look through the dex and you'll find a huge number of pokemon with not only similar, but exactly identical physical and special defense stats. And virtually all of them have their attacking stats balanced correctly right off, with a usefully high number for one and a "leaves-plenty-of-BST-for-more-important-things" low number for the other. The result is that the Unova dex is absolutely littered with things like Stoutland and Leavanny and Lilligant and Reuniclus, and Sigilyph and Scrafty and Darmanitan and Mienshao and Braviary and Excadrill and Escavalier and Crustle and Amoongus and Sawsbuck and... and... and... - pokemon who have nicely balanced stats with everything that they need to function well and no cripplingly poor stats anywhere (or almost anywhere - it should be noted that this has led to a notable number of the Unova pokemon being notably slow, which of course is a consideration in the metagame, and is a good part of the reason that the upper tiers have remained relatively balanced between the gens IN SPITE OF the power creep in gen 5). The pokemon like Swoobat or Liepard - who just don't quite have what they need to make the grade - are the exception in this gen. If you go back to earlier gens, that's simply not so strongly the case. Sure - past gens also gave us great pokemon, and the current upper tiers reflect that. But past gens also gave us quite a few more mediocre pokemon, and quite a few more absolutely useless ones. Sure this gen hasn't introduced an unacceptable number of new Skarmorys or Dragonites or Salamences, but it didn't give us ANY new Unowns or Plusles or Ledians or Delibirds. And in fact, with the DW abilities, it actually went a ways toward improving some of those older pokemon (a sure indication, IMO, that GF recognized the power creep and took steps to alleviate it a bit by improving past gen pokemon SPECIFICALLY in order for them to remain, or in some cases become, competitive).
Now - all that said, I don't care much. I think that some amount of power creep has absolutely undeniably happened, and I think that it's to some degree pretty much unavoidable. As time goes on, they're just not going to introduce as many, or any, new Delibirds, and at the same time, they're going to be looking to outdo themselves. I just can't see them introducing another Ledian - a pokemon with a mind-bogglingly ridiculous and wholly inappropriate stat spread. It's not that they've introduced some unprecedented number of new uber or near-uber pokemon - it's that virtually all of them are at least useable, and a great many of them are really pretty damned good, and obviously so. And I expect that to continue. They'll undoubtedly still keep it somewhat under rein, since the gens need to stay reasonably balanced just so that including past gen pokemon in a new game is a bonus instead of a useless hassle, but I think it's undeniable and unavoidable. And personally, I love it. I'm on my third time through a Unova game and I still haven't come even close to using all of the awesome pokemon I want to use out of this dex. Contrary to so many past dexes, there are still so many out there that already have solid, balanced defenses, at least decent HP, plenty of points in the attacking stat they need with no wasted points in the one they don't and.... well... sometimes really sort of crappy speed, but still......
TL/DR: Some amount of power creep has happened, it's pretty much unavoidable, it hasn't had that much of an effect on the games overall and I welcome it.
