Not really, although I think it depends on how much detail there is in the graphics. For example, the "head-bobbing without ever moving the lips" style of dialogue from PS1-era games looked perfectly fine with those low-polygon models. There simply wasn't much graphic detail in general with those and so, the facial movements were simpy implicit.
However, if you go and add more and more graphical fidelity and detail to the characters (especially if they are styled to be "realistic" looking), it'll look rather off to have all those other little facets of the face just about right, except for the lip synching. It's pretty much part of the "uncanny valley effect"; the more realistic/ detailed something or someone looks, the more likely are we to notice minor inconsistencies.
As a comparison, I'd like to point at the Special Edition of Monkey Island: In the original version of the game, everything looks about as realistic and detailed as it could at the low resolution and the extremely limited number of animation frames in the characters looks about as natural as it needed to. In the new Special Edtion, they kept the number of frames for every animation, yet updated everything else to cartoony HD-graphics, which, for example, results in Guybrush looking like he's sliding across the floor everywhere rather than actually walking. The lack of that particular detail simply looks off.
That said, I'd really prefer developers to put effort into other, actually important, aspects of their games instead of pissing away time, money and diskspace for something as inconsequential as precise lip-synching.
By the way, that's also an argument that could be made in regard to voice acting in games in general. Imagine how much more freedom devs would have, if there wasn't an insistence to have (nearly) every single line in an RPG voiced nowadays...
