Golden Sun has as many lovers as detractors. Many think it is over-rated. I don't, I loved the GBA versions. If a Wii version had the depth of a Namco or S-E rpg, then it could have to be awesome. A DS version could be perfect as well.
I never played Ogre Battle. From memory, it is an SRPG? I can't anything bad about that.
As for a Mario RPG and FF characters, it could work, but would probably be better without them. Just make a decent, full blown FF for the Wii separate and leave the crossover to KH. I find it difficult to understand how people can criticise a 'concept' or idea about a game. It hasn't even been made yet, so such strong negative views seem rather pointless.
Bring on any of these games. They would be hardcore right? Just what the detractors are calling out for.
Temporarily banned until further notice.