For me, it's without question that the Johto, Hoenn and Sinnoh leagues were better than the Unova league. The only league that people could make an argument for being worse than the Unova league is the one in Kanto, but even then I'd say these people are clutching at straws. The Kanto league was better than the Unova league in my opinion, mainly because there was no expectations of Ash at the time. Ash was a rookie, it was his first ever league and I was just happy to see him battle a couple of episodes centered around battling rather than humour. The battles against Mandy and Jeanette were cool, I liked the elemental battlefields, the fact that Gary was beaten kind of threw me off guard and most importantly, I liked the way Ash reacted to his defeat against Ritchie. That loss contributed to his development as a trainer, it gave him the kick up the *** he needed. The only pro that can be taken out of the Unova league is the battle vs Stephen, everything else was e_e.
There was so many things wrong with the Unova league. Little to no strategy used by Ash, one of his most recognisable character traits has always been his ability to come up with a novel and unique strategy in the heat of a battle. The closest we got to seeing this side of Ash in the Unova league was when he came up with the iron tail/electro ball combo, and even then, it didn't really make sense. Serperior had earlier dodged an electro ball with consumate ease but the minute Pikahoe uses it in conjuction with Iron tail it suddenly connects. Serperior was portrayed as a God of speed, how would using iron tail to fire electro ball make it any more difficult to evade? And more importantly, how was it strong enough to knock the serp out? The icing on the this **** flavoured cake was that Ash not only regressed in placement, but he lost to a total moron with a handicap of -1 pokemon. After defeating a Darkrai that nobody else in Sinnoh league could beat and a Latios AND finishing in the semi finals, the Unova league was a really hard pill to swallow.