I mean, what is there to be upset about?? Sure lots of people wanted to see Chimmy evolve in due time after he joined Ash, and then wanted to watch it kick the snot out of Paul in a battle, but I think it's rather appropiate...I mean, the last time Chimchar battled Paul, it went completely crazy because Ash couldn't control his blaze ability, nor does he want to use it...
But it doesn't matter much to me because Chimchar is getting nothing but the best amount of screentime being on Ash's roster, totatally PWNing at gyms, so I think it's fine...Besides, it's almost like how long the writers took to evolve May's torchic...But chimmy wasn't er, um....neglected and got much more screentime than it...And in the Next arc at the end, Blaziken...
I wouldn't worry about it too much...I can see Ash probably getting Infernape in the future...not anytime soon though...