Obviously this is just going to be guess work and discussion but I'm bored and I thought this topic might get some discussion going and get out imagination fired, rules for Smaug!
How do we think GW will do it and how do you want the to do it. I personally have been thinking about this topic for a while now so thought it might be a good idea to ask few questions on it
1) Do you think they will make Smaug a dragon with all the dragon with all the upgrades and maybe some special rules or go more unique
2) How big do you want Smaug to be, this initially sounds like a fairly simple question MASSIVE but the bigger it is the more you run into control zones issues and terrain problems, fly counters this a bit but you can still see why a huge model might be problematic. Also think of the financial cost GW is going to wangle every £££ they can out of him
3) How powerful do you want Smaug to be again seems simple (stupendously) but again if he is a huge model with fantastic stats he might be to expensive to field consistently and may fall into the same role Sauron does of just being to expensive. Would you prefer a model that was less powerful but you were capable of using him more often so the hopefully great physical model doesn't spend the entire time sat out of view
4) What special rules do you want/expect him to have, personally dreading that they might give him some rule that makes him susceptible to bow fire therefore making him useless/venerable in game. I hope they do a rule making him bad against Bard and Girion e.g each wound they cause does D3 instead, therefore making him extremely vulnerable against them given there special rules as it should be given the lore but still badass against everyone else again as it should be in the lore. As for other special rules maybe something about his intellect (high courage maybe or more spells) his size he is the last great dragon maybe a special brutal strike (like Beorn has) or something to do with his lust for wealth.
So guys and girls let your imaginations run wild