I wasn't really trying to debate, I just thought it would be fun to throw in those screenshots for people to view. I personally think PCE could handle Secret of Mana and Seiken Densetsu 3, but technically it would have to be proven.
Colors are pretty important, so the screenshots you and I posted are a great way of showing how the colors would've came out, so that's one thing down and it looks like it did a fairly decent job.
The map indeed would probably be the hardest thing to port. Whether or not it would be possible to port, I don't know. A programmer would know better than me on that. Chris Covell's Axelay demo looked great and is a bit similar to the Secret of Mana map, so it's a tough call in my opinion.
Transparency can be faked in many ways, so it depends on how well the developer and immitate it.
I don't know why tons of sprites would have to be removed and I really don't see why they would have to be much smaller
? Especially if it's a Super CD or Arcade CD game, it would have plenty of RAM for all of that. The sprites in the game are pretty average-to-small for the most part anyways, even the bosses are usually nothing huge.
I haven't played through SD3, so please fill us in on what would be impossible from it to port on PCE or Genesis for that matter. I've only played a little bit of the game and thought the graphics looked great, but that was mainly because of the artwork and coloring.
By the way, that Mario 64 converted screenshot looks great! (seriously)