General answer for the title:
I'd go all USA-Republican on this one and say that is you didn't pay in advance for it (which is not the case here) STFU and wait for it. Imagine it's just another mod some dude is doing. Only this time it's some professional team and at the end you'll have to pay for it. Would you pay for some half-done thing just because you were out of patience? Good things come to those who wait (unless they get off their asses and do it themselves). Blizzard is taking
YEARS not only to produce their games but to have the right
concept and
balance them. The original M&B was in production for a lifetime because it started as a hobby. It got to be such a great game because of the huge support it got from the fans, not because people were whining for an update. I understand your frustration and maybe the marketing strategy the authors chose was not the best given their current fanbase but I think there's no need to pressure the guys.
As for dual wielding... I think it's not about coding it but about making it ergonomic enough to use it. Please imagine you's have two more buttons to press in a fight: a left hand attack and parry besides your right hand attack and parry (on the mouse-right hand) and character movement (WASD and SPACE BAR on the left hand). So unless you come out with an extra hand and/or fingers you'll have to have some PhD in behaviorism in order to implement this.
All the best and keep up the good work