Something like this always raises many questions and "what ifs"...
Universal has a good product in Marvel, and they màke money off of it, but it's a direct competitors property now, and they pay them royalties...not to mention they really can't do anything with the island anymore or it becomes a breach of contract and Disney gets the rights from them then...
So if you were Universal, would you throw a number out there, go for a similar repkacement that will still bring in money, or continue to roll with what you have?
Oh...and what would be so wrong about Batman and Captain America both being featured in Universal parks? You know Marvel and DC have done crossovers numerous times. I don't see how it could hurt.