That would work excellently, yes. Alternatively, you could go for a more radical separatist who was previously disregarded by the unionists as a nutjob, only to come back in force later and now be a threat against them.
Essentially, Ron Paul (RON PAUL RON PAUL) comes in two flavors: "You could have stopped this from happening, now it's too late." and "All that has transpired has done so as I have foreseen, now who's crazy?".
Well, this is really annoying me because that character is divided across several people in Scottish politics. The only one I can really think of right now is Henry McLeish, former First Minister from years gone by. He was a Labour leader in the early 2000s, but he fell out of favour due to a few minor scandals and his resignation. Since the independence debate began he's been extremely critical of Better Together, saying that Scotland could "sleepwalk into independence" and criticising their extreme negativity, as he perceives it. He routinely challenges their scare stories and demands a positive case be made.
Since he began making these statements, Labour have sidelined him as a loony and basically dismissed everything he's said. The problem with him is that I don't think he's crazy, I think he's a pretty reasonable guy, one of the few decent men in the Labour Party. He doesn't fit the Ron Paul mould.
One guy who does look crazy and is crazy is Tom Hunter, one of Scotland's wealthiest men who made a few interventions in the debate, saying stuff like "Better Together is incredibly negative and making nonsense scare stories, Yes Scotland aren't giving out enough information", managing to be incredibly militant about "getting the answers ordinary people want" etc. The problem is I'm not sure if he fits the mould either because he's not a politician and he hasn't made strong enough statements on the lines we're looking for.
The guy who fits the mould of "separatist who was previously disregarded by the unionists as a nutjob, only to come back in force later and now be a threat against them" would actually be Alex Salmond and the rest of the SNP. He's not a "radical separatist" by any means but he's a good example of a very underestimated foe that is now biting the Unionists in the arse, metaphorically speaking of course.
So I think on the whole Henry McLeish fits the "you could have prevented this, why didn't you listen" bill best, but he's not crazy enough. Well... he is a bit crazy I suppose. Tom Hunter is crazy enough, but he doesn't fit the "you could have prevented this" thing so well. He does commission polls though so maybe he would work for the "it's happening" thing. Alex Salmond is the most well known figure in this entire independence debate and he is the underestimated politician, now causing earthquakes. He pursued the addition of a question related to increased devolution on the ballot paper but the British government refused, so that may work for the "you could have prevented this" thing. I can't really make a decision here though, it's hard to say.