imp, I am also of strong opinion that a block cycle would do more harm than good for Wyrd. Too many hours of hard work go into painting up a crew proper to have it useless after a book or two. Clix figs or Magic cards require the time it takes to get them out of the box or wrapper to be ready. No real investment required after the fact. GW is losing a lot of ground, I think, in part because of their codex cycling, power creep, and unit obsolescence. After 10 years PP is stronger than ever, and all their units are more or less like theyve always been, and still present in the rules. I can see new strategies and schemes cycling in and out, but I cant see the figs doing the same. People will keep buying Wyrd's stuff if we're given the illusion that we want to buy it, not because we HAVE to. :happypuppet1
As for a new faction, I dont think there will be one. I think they planned out the factions pretty well, and unless the Tyrants get their own faction, I cant think of any reason to add a 6th. I hope there will be new masters down the road, but im fine with the current 20. Im sure book 4 will be all about special forces and henchmen. I think they will be the key to diversity. Im sure Wyrd has been thinking about what Malifaux's direction is for several years ahead. Just trust them. They have been doing pretty awesome the past two years if you ask me.
Also, a prediction on henchmen: there will be rules to make any minion a henchmen(take a look at the ronin's drifter rule), making tons more crew leaders.