David Vonderhaar at Treyarch has been excellent at correcting design and balancing mistakes from one Call of Duty to the next. He admits he makes mistakes and he corrects them. Better than some other devs who never admit they ever make a mistake, and thus never correct those mistakes in the future.
I actually really enjoy Treyarch's Call of Duty games. Each one is reasonably different from the last, and they usually make pretty major changes and improvements. I look forward to their games and just completely ignore anything with Infinity Ward's name attached these days.