PokéSpe will stay a manga because it works well as a manga. There's no sense in adapting something when there's already a comparable show. If the regular PokéAni ever stops being made, maybe then we'll see a PokéSpe adaptation.
I don't think most people just let Ash using hax just slide. I mean, most people are really annoyed when he gets to use hax, just like when other characters use hax. It's one of the most annoying things and indicative of kind of lazy writing.
That'd be interesting. But honestly that's almost like how BW was with the "rivals". 5 out of 6 of Ash's tournament rivals were more friends than anything (Bianca, Stephan, Cameron, Luke, & Virgil were friends, Trip wasn't really) and Georgia and Burgundy got along with the group as well, amazingly enough. It really felt like the whole cast was in it together. I'd love to see that kind of camaraderie back in XY, only hopefully it would be better written.
It's not impossible, no, but winning a whole tournament with one recently obtained, first-stage Pokémon looks a lot more like hax than if it was second-stage or if it was a multi-Pokémon battle. See, I could see him getting through some tough opponents with a three-Pokémon team that includes Goomy, and having Goomy come through for him in a tight spot. I could also see Goomy and another of his Pokémon working together in a double-battle scenario to take out opponents with strategy. I just think winning with just Goomy would be a little over-the-top.
The way you're presenting it, Ash would have just got Goomy and then suddenly went on to win an entire tournament filled with powerhouses. But the thing is, Ash wouldn't have had enough time to learn Goomy's personal strenghths/weaknesses/abilities- he wouldn't know how to use it to its full potential yet. Ash's wins come from being in synch with his Pokémon and utilizing their abilities to the max.