Muffin Man, I believe Flash was referring to the possibility of these two fighting in a match that didn't concern anyone but themselves and their on hand attributes. Sinister's clones and Doom's robots aren't included in this one on one 'bout, as I read it. Anyway, I'd have to give this to Sinister personally. Few have figured out how to truly destabilize Sinister and his body is not unlike that of T-1,000. No matter what physical punishment is applied to it he still keeps going. Not to mention the fact Sinister has super speed, agility, strength, durability, psionic powers, teleportation abilities..etc. Unless Doom can find some way to readily develop enhanced amounts of Telepathic and Telekinetic powers ( which seem to be Sinister's only bane ) then Victor is DOOMED. ( Rofl. I made a funny. )
Maybe, but to be fair, no one truly knows just how many tricks Doom has in that armor of his. And remember, it's defensive capabilities are enough to take shots from some cosmic beings. And don't forget his mystical knowledge. Although I might look to Sinister at the start, I'd never put anything past Doom. Oh, and what if he's wearing his recent magic armor?
As I said in the Doom vs. Magneto thread, Doom has a pretty lousy record engaged in personal combat with opponents. His specialty is more in plotting to do something and then doing it. So if the two were to suddenly get into it, Sinister would very easily own Doom. There's very little Doom could do to defeat Sinister. Sinister is one of those annoying super-regenerative villains who can seem to recover from everything. Doom would have to have some kind of device to teleport Sinister into another dimension to win.
*waits for someone to post "Doom has tech like that! He's Doom!"*
But how could Doom prep for Sinister? Does anybody really even KNOW anything about Sinister, his powers or how they work? I could see Doom preparing for Magneto, because he's a public figure and his powers are based on a well-undersood scientific concept. But how do you prepare for someone like Sinister?