(Replying to five-year old thread!) I was thinking of making a similar proposal, but decided to search first because I suspected someone would have thought about it before, and here it is.
Sometimes I really want to see a node reputation but can't decide which way to vote. Not because it will help me evaluate the node better, but because sometimes I have a morbid curiosity to see what the community's reaction to the node was. This happens with some controversial nodes.
It's sad that the powers that be decided not to add such an option. An alternative we have is to vote at random when we wish to abstain. In the long run, these pseudo-abstain votes should mostly cancel out. ;-) But a big drawback of this approach is that we would lose information about the "controversiality" of the node (a node with a community reaction of zero reputation and zero votes is not the same as a node with zero reputation resulting from 50++ and 50--).