Peter from AF #15 to New Avengers changed a lot, but it was a natural change. It was part of growing up. One reason why I like Peter and MJ being together isn't just because I like MJ as a character (althrough that is part of it), it's because we got to see Peter grow as a Person. The Lee-Ditko era portrayed Peter as someone who was a bit selfish. That's kind of the whole point, he is a neurotic teenager who had the weight of the World on his shoulders, he was going to be a bit of a jerk from time to time. But we love that era regardless because there is growth. Would the Spider-Man from Amazing Fantasy 15 be able to pull himself out of machinery? Probably not, but the weight of 30 issues led to that point.
There was a progression there.
I actually do see where Slott is coming from, as the BND era is kind of a regression to the Lee-Romita days. Peter was in that stage where he was old enough to deal with adult responsibilities like having a job and being independent, but young enough to deal with relationship problems and be outgoing. But this was a tiny era in the history of Spider-man, but it was the era folks like Quesada and Slott grew up with. That's what they remember and that's what they want back.
The 80's and to an extent, the 90's are actually pretty good eras for the progression of Peter Parker. He is an adult now and he doesn't go out all too much. He had to be the Peter Parker who he is. Mary-Jane being an actress and Model is actually a pretty good way to not only show that he doesn't care if his Wife earns more than him, but also allows him to be Spider-Man and Independent without any financial issues.
And while Marvel tried to throw that all away with Clone Saga and beyond, JMS brought it back and made their relationship the central focus of his fun. This was the Peter Parker we wanted and this was where the Peter Parker from Amazing Fantasy #15 would go.
But now with BND, Slott and even Spencer to some extent, he has become the teenager from the Romita era again, struggling with a job and relationship issues. Spencer has tried to fix that, but his run hasn't been about them. It's been more to do with their Marriage and how bad OMD was. For a run which should have focused on the two of them, they feel more like supporting Characters. Even with MJ going away for a year, there wasn't much interaction between them. We got a few issues but that was it. We never got to see how much Peter misses her, he only says he does.
What Spencer needed to do was progress their relationship from the JMS era instead of responding to OMD.
I like his run enough, but it's a tribute band instead of being inspired by.