I'm excited to play with RGSS3. $175 seems way too high for what it is, considering it doesn't seem to be much more than an addon to RMVX (though obviously a separate program; it seems similar to the shift between RMsk and RM2k3).
I would hope they replace the tileset system or, if they keep it, at least provide an alternative. It can be well enough that they wanted to make it easier for new users, but there is really no reason why they can't allow you to swap in new tilesets for new maps. The limitations on mapping in VX have never made sense.
I like the noteboxes for actors and hope that they include an ability to add new options to the event commands. It would be that much neater. I would love it if they would just add an ability to create plugins that would, for instance, add new tabs to the database for configuration, but I suspect that is wishful thinking.
Face Generators have always been a little expressionless and hard to give life to characters, but the built in character generator is a good idea I think.
Anyway, I am definitely excited to see what happens with this. It does cost way too much though. Hopefully that is reduced for the English version (if there is one).