My consensus was pretty much mentioned by fellow freaks like Robbie and Evilface but here are the reasons why I think this tanked (I'm still really glad I have one and like it a lot)
1. Hot toys took too damn long to make it. They snoozed on the hype of the lisence and by the time it came out no one cared anymore.
2. They should have started with Nyteri. Now this is a little bit the opposite of the problem with the Watchmen as they did start with the main character but they didn't start with the most popular and they've pulled off this moronic idiot move too many times before. Watchmen got killed by starting with Specter, first class never got off the ground because they started with Xavier and not Magneto. They are going to kill Prometheus both because its been too long and because they are doing Shaw and not the Eingineer.
3. The design of the character, jake looks pretty cool all things considered but lets face it the movies strong point was not the character design it was the effects and the experience. The characters always reminded me of poor anatomically incorrect badly proportioned cheesy fairies that a 13 year old girl would draw.
Agreed. Although in the case of X-Men First Class they still haven't even officially announced Xavier and put him up for order so we can only speculate that he probably wouldn't have been as popular as Magneto.