(This post has spoilers. Stop reading if you haven't watched the anime entirely or until episode 175).
Just because the guild Fairy Tail won the magic games doesn't mean that the show is good. Its about the show, and not the guild. Erza's battle? Pandemonium? I agree with that. That's my favorite episode of the entire series. Anyway, its not only about time-skip.
The character development is extremely poor. Only Lucy and Wendy actually have character development, and a bit of Erza. I find it extremely boring to watch a series of 200+ episodes in which characters hardly change. Most of the anime do better character development even in 12/13 or 24/25 episodes.
The worst thing about Fairy Tail is how the characters actually use friendship and willpower as a legitimate source of power during battles. I will agree, that to a certain extent, it can work but Fairy Tail takes it to new heights. It doesn't matter anymore against whom the characters are fighting for.
The characters are reeeeaaaally stereo-typed. It has a pretty big cast so you'd expect at least a quarter of them to be interesting but no, there's only three to four intriguing characters in Fairy Tail. Even the villains are boring as hell. If even the heroes and the villains are boring, how can you even expect the story to be good?
And not to forgot all those...Deus Ex Machina... or rather... Deus Ex Mashima.