this will be immensly helpful
since we have scattered rock now able to have a small tile of rock within it it will be very helpful to make rock into a city or town tile. ah2 has no town tiles. we fly only over farmland never reaching the cities hehe this will be helpful in making good terrains and variety in them. town tile instead of rock will be excellent
as to snow tile, its not needed. no map maker uses this tile seriously in ah1. its just dead weight and contributes nothing that can be used throughout the map.
with snow changed to scattered trees it would only need (it has only 1 transition) its single transition to intersect with the grass tile
this will help out a lot if it can be done.