QUOTE(cribbidaj @ Nov 6 2009, 05:02 PM)

Is there a less tedious approach that allows you to use a set of phoneme poses and animate between them smoothly?
I presume you have done the lipsynch tut in TAoA:M and are doing that procedure correctly. If not give it a try.
However, animators have been getting away from preset mouth poses for lipsynch because of the same problems you have encountered and tend now to directly keyframe the mouth shape for speech.
At a minimum this will use a control for wide-narrow on the mouth and another for jaw up-down and maybe a third for puckering-curling the lips. More elaborate schemes are used but just that will get you decent results.
Jason Osipa's book "Stop Staring" deals with this approach.
But it's not
less tedious. It's a bit more work for better results.
Actually you can do a lot with just jaw up-down is your body language is doing its part. Here's one I did
for an assignment where we were only allowed to use jaw up-down.