Personally, I have no problem with someone else other than GDT directing PR2. I'm sure the new director, whoever he is since I never heard of him, will probably do a fine job. In my mind the more kaiju movies the better. BUT...I just think it's a pitty because PR was such a special movie because of GDT. It was his movie, he made it because of his love for Godzilla and the kaiju genre. I also agree that the man puts to much stuff on his plate, most of which never sees the light of day. I have no idea what the real reason is for him not directing PR2, but if it's because he wants to concentrate on other projects, then I am truly disappointed.
However...and this just pure speculation on my part, what if..WHAT IF...he backed out on PR2 because he was offered the directors chair for Godzilla Vs Kong??

Now that would be totally awesome and a dream come true!