Anyone can read the bug report there and see what actually happened. Nobody even tried to detail what they needed until the VimFX came around a year ago to do so, and to begin workin on an experimental API. That experiment didn't really bear fruit until TWO MONTHS AGO, when the Firefox devs were knee-deep in the release cycle of their biggest product launch since version 1.0.
So yeah, the Firefox devs didn't have much to go on except inactionable "just do whatever Vimperator needs" junk, and no other vested interest seems to have lifted a finger to help the VimFX guy speed up his work on the experiment after he finally got the ball rolling, so blame doesn't really rest on the Firefox devs here.
One of the lead Firefox extension API devs is also the primary Pentadactyl (and former Vimperator) dev. I'm sure they were aware of exactly what was needed for that and similar extensions. They also made it clear from their earliest announcements that they intended supporting these extensions.
It simply isn't a priority which may be fair enough.
But the full picture also includes the fact that if all people were willing to do was wait for someone else to do the work, then they really have no high ground to complain that it didn't get done in the time-frame they wanted.
Other addon devs did help push things along, and they got the abilities they needed much sooner. We can only excuse ourselves so far before we share in the responsibility for things not getting done.
