I like Ash because he has the Luffy/Naruto/Goku like ability to turn almost anyone he meets into his friend. Obviously they need some enemies to have a sense of drama and conflict in their stories, but for the most part...
I also like Ash because a few times each season he comes up with pretty interesting strategies. (Counter-shield ftw!)
But, his cons list is far more intensive.
I hate Ash because he's a noob.
He seems to learn from his mistakes, (arrogance being a major one) and he turns around and makes the same mistake again, while wondering why. >_>
He didn't block Butterfree from finding a mate, which is understandable and even likable. Charizard is off getting stronger with people he can relate to which is neat, and he said up-front that he would help Lapras find it's mother which meant, eventually, letting her go.
But, for Pidgeot and Primeape he had no excuse!
If I recall he left Pidgeot behind to protect some lesser evolutions from a flock of angry Spearow/Fearow. The same ones that attacked him and Pikachu in the first episode, no? That was AGES ago and they should have all evolved enough that they can handle themselves now. Go get your Pidgeot, Ash!
Primeape was being trained into a top fighter in it's own right. This was the same day, if I recall, that Ash and Primeape truly bonded with each other. Again, that was ages ago and, by now, he's either one of the best Tournament-worthy Primeape out there, or he's clearly not cut out for it. You'd think his original trainer would have dropped him a line or something in all these years. Go get your Primeape, Ash!
Then, there's his Pokemon. They've won some truly epic battles against all odds. Then they've lost for no reason. I.E:
Dragonite hit Pikachu with Hyper Beam.
It wasn't very effective! Pikachu used Thunderbolt.
Dragonite fainted!
Metapod hit Pikachu with Tackle.
Pikachu fainted!
Yeaaaah.......about that. >_>
Now, let's talk about Team Rocket. Ash is ALWAYS surprised when they appear!
Any other sane and competent person who'd seen those 3, even just 3 times, would recognize them on sight unless they'd really put in work to disguise themselves. Short, furry man that looks like a Meowth, tall and arrogant woman with long red hair, and a tall, effeminate male with short blue hair? Should be easier to spot then Waldo. Glasses and fancy suits do not a good disguise make. Not being able to recognize the 3 'Gym Re-modelers' as Jessie, James, and Meowth is like not being able to recognize Serena as Sailor Moon. Really now...
Speaking of Team Rocket, they suck too. The few, 2 out of 10, times they managed to catch/outsmart/overpower Ash and his Friends, they still turned around and lost to the 'Character of the Day', whether it was Gym Leader or some kid with 2 badges. If I were them, I'd find out exactly where Ash and his Friends were currently staying at, go to some nowhere place 25 miles away, catch every rare pokemon in the area (with a Pokeball) virtually unopposed, and THEN come challenge him and his friends to a battle. Even if by some miracle Ash STILL managed to win, Team Rocket could still send their own rare pokemon to the Boss and finally earn some Brownie Points in their career.
But. this is about Ash.
Ash has enough interested females to form his own harem. He's even been kissed by some. (3, to be exact, I believe.) But, he shows no interest in them at all. This is highly annoying as this show could do with a bit more romance to hold peoples interest.
They have epic battles/plots, outside of Gym/Contest Matches, like once every 25 episodes. The rest of the time is bland, uninteresting, who's-that-pokemon stuff. This would turn anyone away after awhile.
BRING BACK MISTY!!!!
And, of course, Ash has never won a Major League, nor have his friends, never ages, never dies (Like Love Hina's Keitaro) which is actually kinda cool, and never catches awesome new pokemon even when they practically jump in the Pokeball themselves.
Just my feelings, though.