it may have the biggest install base, but the majority of that install base may not like the game, and in case you have seen, hard core games don't seem to sell that well in japan, it's the casual games that sell well in japan these days, of course this is just a japanese trend.

Judging by the sales of the previous games I think it is safe to say that most gamers will not like this game. The Wii will offer more profits for a lower cost though. There would be no point to even try to get HD graphics so the development cost would go way down. As development cost drops then so does the number of games you have to sell to make a decent profit.

it may have the biggest install base, but the majority of that install base may not like the game, and in case you have seen, hard core games don't seem to sell that well in japan, it's the casual games that sell well in japan these days, of course this is just a japanese trend.

Most people don't like Suikoden.  It's a niche franchise at best.  Niche franchises simply won't be on the PS3 and 360 because it's way too expensive to make them on the PS3 and 360.  I doubt you'll ever see Harvest Moon PS3 for example.  Also games like Odin Sphere 2 switched to the Wii because of how expensive PS3 and 360 development is.  Small franchises like Suikoden are pretty much destined for that road.  It's either a Wii version or no version. 

If you wanted the majority of JRPGs, the 360 and the PS3 weren't the systems to buy.  Only the mainstream RPGs will be able to survive on the systems, and the majority of good RPGs aren't mainstream.  As far as hardcore games on the Wii in Japan, Dragon Quest Swords has still outsold EVERY PS3 and 360 game in Japan, and Super Mario Galaxy has more than doubled the sales of any PS3 or 360 game in Japan.