Huh, turns out it's been just about two years for me, as well. Sure has been a long ride.
Turns out I lived up to my name. Oopsie. Also forgot to say, thanks for starting the thread and sharing your opinions, let me think about stuff a bit, too.
I agree, it's not as new anymore, it doesn't feel as exciting anymore, it doesn't feel as good anymore. As Scootapuff mentioned that's just how life works, at some point the crush and the exciting new couple love runs its course and you move on to the next part of the relationship that just might not be as exciting as the previous one. Despite that, it's a shame. I'm not trying to make excuses for seasons 2 and 3 and the show has undoubtedly changed somewhat, but maybe (or even probably) a good part of my problems and lack of enjoyment came from me wanting to relive and re-experience the feelings I felt when I was originally watching the show and discussed it. Wishing for things to be like they were earlier.
When season 3 ended I said I considered it the series finale. Now that season 4 is right around the corner I've started to get hype despite all the negative feelings and the decisions the show staff has made and I can only think it's at least in part because of me (albeit artificially) separating the new season as a new show. I think with that it's easier for me to accept that the show just isn't the same anymore and I don't get frustrated when things go wrong. Maybe I will, maybe I won't, only time will tell. But I'm still getting excited.
For me, pony has become an intrinsic part of my being and I do believe I've transitioned to the "calmer love" part of my "relationship" here. I still love the little ponies and the world, maybe even more than I did a year or so ago, but it's not as impulsive as it was. A lot of the fiction I read is ponyfics but it isn't all I read anymore, it's become one thing among others which is just okay.
As for the fandom, my interactions with it have mostly been through reading fics, looking at pretty pony pics, checking EQD for things and posting on /pony/, be it here, or Pchan as it once were. Ever since s3 ended those have mostly been on hold, except the few fics I follow so I can't really say anything about the fandom at large. I suppose I've noticed some of the musicians don't put out as many pieces anymore, but that could just be my perception of it.
Long post is long, the ride never ends and in the end I'm not sure I'd even want to get off Ms. Pinkie's Wild Ride. There is a lot of potential with the setting and the characters still if they just realized that potential, and I know there is at least one song and one episode I'll very likely enjoy when the new show rolls up. I can't help but feel excited. It is more pony after all!