Silva barely engaged Lietes and Maia because they also did not engage him. It wasn't their bjj that kept him at Bay, it was their unwillingness to engage,because they know Silva likes to counter. They knew as well as he did that they were no offensive threat and were hoping against hope that somehow the fight would end up on the ground.
At least a wrestler has the option of offense and would put Silva in a position where he has to perform, even if its to stuff the takedown. If a BJJ guy has no wrestling ability he is no threat what so ever.
Having said all this, I think Silva KO's Rashad in the 1st round..

But keep in mind, all along my argument is based on theory. Rashad has the tools IMO to give Silva problems, but his history shows me he wont use them properly. Palhares like 90% of bjj guys,may have the tools, but is lacking the other tools necessary to use thier main tool..meaning..they don't have the takedown ability to use their bjj in the first place.
Its been a looong time since his submission defeats, one of them a fluky sub anyway and his BJJ has improved greatly since then. When he first started fighting he really didn't know bjj like that. It wasn't until he hooked up with Nogueira. Since being in the UFC. You have to go back to Lutter to find a BJJ guy that has mounted any offense on him. And ironically, his increase in takedown defense has made it less likely for BJJ guys to get him down more so than wrestlers..