I'm not trying to complain here, but I find him to be a Gary-Stu. Reasons:
-He has a lot of girls falling over him (both human and Pokemon)
-He's been the chosen one multiple times.
-He's befriended many legendary Pokemon, while others are lucky to even see one.
-He has no real notable flaws, only minor ones, but they really don't affect him. He's impulsive and brash, which, in this anime, is synonymous for "brave and filled with willpower".
-He "loves Pokemon more than anyone else". They fail to actually show it, but they sure tell us a lot.
In conclusion, I think he's a Stu. Maybe not as bad as some other anime characters, but still one by Pokemon standards.