The Kanto arc is still the best, because it provided a bit of a twist that wasn't bad at all, and was able to make some points without becoming overly stupid.
The Johto arc sucked ass at the last second and was made super-unnecessary with the backstories given to Blue and Silver to tie them in with the Mask of Ice. It started to feel heavily forced, and the end of it was complete crap.
The second Kanto arc was fairly nice, and helped expand some things and characters, and the characters were nice additions until Sird started becoming major bullshit incarnate.
The Hoenn arc made Maxie and Archie seem like total fucking psychopaths when they were just wanting to expand their respective elements for more Pokemon. It was more taken over by Sird's stupid bullshit in order to give a really awkward and stupidly introduced twist.
The Sinnoh arc was OK, just a bit boring and nothing really stood out.
The Unova arc makes N such a bleeding heart that I just want to stop reading it and shut it out.
The HG/SS arc is fucking stupid. Petrel is the only character worth a shit in it, and he gets drowned out by Archer's shitty fanaticism. And the ending is just so fucking 'wonderful', "HEY PRYCE, I KNOW YOU KIDNAPPED CHILDREN, BUT CAN YOU RAISE MY SON S'MORE SO WE CAN FIGHT ONE DAY WHILE I HAVE LEARNED FUCKING NOTHING? THANKS"
tl;dr, It's brought down by the stupid shit rather than the good shit.
