<p>In short: NO.
First of all, Marvel will not use villains that are not under their control (mind, that all Spider-Man rights are still controlled by Sony).
Second, Green Goblin, seriously?
He could be taken on just by Spider-Man or Iron Man.
I'd rather see <i>real</i> Mandarin. You can bring Leader, Magus, Lilith - the list goes on.
I admit that some of the most lucrative villains are in possession of Fox these days (Doom, Galactus, etc), but aside from them there are still options where to go after Thanos.
</p>