I'm going to be the wet blanket here: Platinum needs Sega, not the other way around. Not that I put much stock in the Sega guy's comments as he doesn't seem that high up the totem pole, but if Sega doesn't think Madworld 2 is worth publishing, then Platinum games will have to look elsewhere.
I like Platinum, but its sales track record is so-so, which really limits its leverage to get sequels to not-that-popular games out on the market.