I hope UDE releases sets at a rate that maximises the amount of money they make. Given that's probably their goal as well, and given that they would be able to estimate it better than I, I trust UDE to make the call. No matter what rate they choose, some people will say 'too fast!' and others will say 'too slow!'. I figure the game will be ~as expensive to collect as other card/minis games.
UDE is probably conscious of what happened with the TCG, where the release of The Dark Portal took so long that HoA had gotten a bit stale by the time it arrived. There are only 66 minis in the first set. I'm not unhappy that we'll get another group within a couple months.
A Mini Journey