I agree with this. Both wardens and guards have plenty of skills that can be used to get back to the top of the aggro heap on a target in less than 10 seconds time (much less, depending on what's off cooldown) so with proper coordination and communication there's no reason CV can't fulfill its function the way it is now. Whether it's a raid or a fellowship, it's purpose now is to send the mob back to the tank who had it for long enough to get ahold of it fully, which is a lot nicer for a tank than having to chase the mob across the room to wherever the ranged DPS classes are sitting.
One thing to keep in mind is that perceived threat bonuses scale to be far more useful than true threat bonuses the longer the fight goes on. It won't be particularly great for getting stuff off of you at the beginning of a fight (although that's really where DW shines) but later on in the fight when there's a lot of aggro on the table a threat drop of 25% would be enough to get a mob off of you and back to the tank in any situation barring a full aggro wipe. It has the potential to be very powerful if properly used if you're communicating with the tank that until he does some more threat skills you will still technically have aggro.
As for our threat in general: I am withholding judgement until I'm able to run tests with a tank I trust when it comes out. I've only been able to run one instance on BR, with a warden who was relearning how to tank, so I can't really say one way or another how bad it will be. I've noticed a definite difference in the past between when I was remembering to use CV consistently and when I was not in how much aggro I was pulling, and now we've got the damage bonus without the threat bonus. It really could be a pain for tanks, but really, given the amount of threat increases they've gotten in ROI I've been hearing constantly about how much easier it is to hold threat than it used to be, so maybe this will just restore them to actually having to work a bit for it. I'm hopeful that whatever problems ensue will be manageable with our existing skills combined with this new CV mechanic.
EDIT:
I was just reminded when posting in another thread that DF has been buffed. Hopefully, that buff affects its aggro reduction ability as well. If this is the case, it could very well go a long ways towards closing the gap CV has left, especially when fire traited, and could help continue to motivate people to trait fire now that lightning has been buffed.