Just to backup what OLF said: if you enjoyed TH2, then there’s absolutely no reason why you shouldn’t get TH2AD. The titles go hand in hand, and it’s really a shame the real TH2 wasn’t both titles combined as one (i.e. they came up with these additional stories and had them in it). I can only imagine how this “wishful title” would have been received… probably rated as one of the best of all time. In any case: TH2AD is like the “second half” of TH2 - you’re missing out on the whole experience without it.
Ah ok, I didn’t realise that different stores had different pre-order bonuses. That would make any predictions very unreliable, but I still think it suggests that the latter tale hasn’t sold as well as minori hoped.