The market wasn't all that great for Regehr. If I remember correctly, the Sharks, the other team interested, were only offering McGinn and some late picks. In hindsight, that still would have been a much better deal.
That being said, dumping Kotalik for a 2nd/Byron was absolutely terrible, but the blame lies more so with the ownership group, who weren't willing to eat Kotalik's salary. So even if Feaster wanted to take the Sharks deal, he couldn't because there was no way Wilson was going to take on that contract.