Welcome to the forum.
You bring up a topic very near and dear to my heart. The possibility of Godzilla returning to a tokusatsu style, or as you put it, suitmation and miniatures, depends on how well that genre/style does in Japan.
If the Legendary Godzilla movie does well at the box office, Hollywood will probably just pump out another sequel. Toho likes the fact that another studio is doing all the heavy lifting and they're reaping a profit off of it. Why would they spend money on their own movie when another studio is doing it for them?
If the new movie flops at the box office, Toho will probably assume that Godzilla needs to be retired and I wouldn't expect another film for the next 20 years or more. Either way, Toho probably won't be producing their own Godzilla movies for a long, long time.
Now if suitmation/tokusatsu becomes popular in Japan again, I can see Toho wanting to cash in on that. Right now the only movies/television series made in that style is Ultraman, Kamen Rider and Super Sentai (Power Rangers). Kamen Rider and Super Sentai are doing well, but Ultraman is practically on life support. If that style of filmmaking becomes big again, there's a good chance Toho will use the same techniques to bring Godzilla back.
But as it stands tokusatsu and suitmation is a dying breed of visual craftsmenship in Japan. I don't think it's going to make a comeback any time soon. That's includes Toho's suitmation Godzilla.
"'Nostalgic' does not equal 'good,' and 'standards' does not equal 'elitism.'" "Being offended is inevitable. Living offended is your choice."