Don't know about Dowie but transfer experience is, of course, another area where Hughes is unproven. On that point I think that Souness' major failure was in transfers - looking at the team now compared to when he came in the replacements are just not as good as the ones who've left.
Megson's a possible but, be honest, if they announced him today would it excite you for our prospects? It's the same with people like Curbishley or Strachan - they'll (hopefully) keep you in the premiership as a low- to mid-table team but without ever challenging for even a top 5 finish. And that's where I think, realistically, we should be looking to finish. Mourinho proved last year that you don't need cash to be successful - and on a much bigger stage than the Premiership. So, that's the answer - let's find another Mourinho ;-)