It's quite clear that you ignored the points I gave above. I guess then you want to desperately believe that the Ash-Greninja arc was bland. They went through through a lot of trials and errors, through a lot of emotional turmoil to master the form, it's not that they instantly mastered it.You're acting like it's a fact that they weren't.
It was bland because the characters' lack of vibrancy and foibles meant it was mostly acted out stiffly or through exposition. I got things were happening but the whole 'Ash focusing on power' was underwhelming because his character was still ace-ish and carefree most of the time (oh, wow he handed Serena his coat a little rudely, such a new found bad attitude ) and Greninja still acted like an expressionless piece of cardboard. Like a lot of things in XY, lifeless execution ruined it.
And you dislike the fact that XY Ash was competent? OK, fine that's your opinion. You like protagonists that have more flaws. But I don't think there is anything wrong with a protagonist being competent and badass- they seem more inspirational to me. But it's not that XY Ash didn't have flaws, he had his flaws which he sorted out through his own. But in my opinion, his competence and maturity made him look more inspirational. Think about his inspirational speech in the Team Flare arc which brought back Alain to his senses.