I have honestly never noticed anything that made me think, "Obvious toy insert" in MLP. I admit that I haven't really cared much about toys in a couple decades, and I never played with MLP toys as a kid, and didn't really know what kinds of toys the show even advertised (I only really knew about the brushables). I still see the occasional EQD post that shows toys, and think, "OH, that thing from episode XXX was a toy? I had no idea." I think a lot of people blame executive meddling for story elements they just don't personally agree with. For example, in one interview, Jim Miller said that the concept for Flurry Heart came from a storytelling opportunity, not as a mandate from Hasbro.
I have very much enjoyed season six, and am looking forward to several more seasons to come. I don't think MLP is suffering from any seasonal rot, it's just that season 5 had some really ridiculously good episodes in it which are hard to top. Season 6 is simply back on-curve.