Yes, I wish that too. However, I've been struggling trying to find a way to get that to work out. It would seem that a distanced Tod and Copper friendship may be the best we can hope for, barring Chomper finding an alternate food source. I fear that LBT will have to stop making movies before they reach adulthood or keep Chomper out of the future films to avoid that little problem unless they start getting creative and willing to take more risks.
Anyway, a little animosity between them at times can't hurt a friendship. In fact, what doesn't kill you, er, literally, makes you stronger. So even if, at one point, they get into a fight to the death, and then change their minds, it won't hurt their friendship in the long run. In fact, it's likely to make it stronger.