Me too. Like at this point... if they brought Charizard back for Megas- which is probable since he didn't do much in Episode N or Decolore- then there's no point in sending him back to the valley in between. Ash should just take him on to Kalos, because otherwise they'll just have to deal with sending him back and then bringing him over again once Ash gets closer to Korrina and there's no point to that hassle.
If I may give my thoughts?
Regardless of how much worth you feel Charizard's return had, I believe that the writers brought him back, with backstory and all, to make him relevant in the coming future. I'm thinking they do indeed intend to Mega Evolve Charizard somewhere down the line, so they reintroduced him so he can be in the eye of the younger audience who weren't even born when Ash first got Charmander.
Thing is though, him bringing Charizard right at the start of his Kalos journey would cause something similar to what happened to the Johto Pokemon: not being showcased primarily in Ash's group's teams as much early on. Despite the resurgence of old Pokemon in Kalos, the new ones still have to take prime focus, and as we know, this is done in the Anime by having Ash only bring Pikachu. So I honestly don't believe they will take Charizard straight to Kalos.
What they will do, I think, is, later in the journey (not sure exactly
when, maybe around Shalour City, maybe later, just sometime mid to late-ish) when it becomes relevant, they will find a reason to return Charizard so that he may go through whatever process is necessary to become MegaCharizard. It would be at a time where there'd be other Mega Pokemon to fight, so it wouldn't be too close to the beginning, though that primarily would be up to the pace of the series. (Personally, I'm hoping that we aren't back to DP-level pacing.)
If they brought Charizard to Kalos right away, they'd have to either have Ash curbstomp everything, up the difficulty of the early opponents (neither of which would properly represent the state of the early game where trainers and wild Pokemon are easy to defeat), or constantly justify reasons for why Ash doesn't use Charizard instead of other potential Kalos captures (plus, if Charizard is with Ash, don't you think he'd have used him when he and Pikachu were falling? :P).
On the flip-side, since Ash's Chaizard is now in recent memory, the writers can now bring him back whenever they are ready to make Mega Evolution a completely focused concept for the main cast, while still keeping the focus on the new Pokemon up to that point unimpeded.
On a side note, depending on how much the writers are willing to showcase the new Mega Evolution mechanic in the Anime, this may encourage them to have more fully evolved Pokemon on the main cast (whether you feel that's a good thing or not), especially later on. Assuming they choose to focus on it a lot, that is. After all, Triple Battles weren't that focused in BW (there was only one in fact) and they could always do what they usually do for new Pokemon, have a Character of the Day or Recurring Character showcase them and be done with it.
Though if Ash gets to showcase a Mega Evolved Pokemon, then I hope the potential Serena does too, so as not to hog the love.
P.S.: If I'm being honest, then I gotta say, that sheer BW hate is kind of a turn-off. :(