I wonder though again... an up/neutral/down is really just a 1 to 3 rating system (assuming we are just going to tally things), and a pick-as-many-as-you-like is a 1 to 2 rating system. By taking away the ability to make nuanced decisions, is anything really gained? People can still attempt the same game regardless of the scale by top rating a few and downgrading the rest, whether it's 1-2, 1-3 or 1-10. Assuming I understand it, the fractional vote system is just that game in a formalized fashion, where it pays off to express strong preferences, whereas in the rating system, expressing strong preferences is much more likely to land you something you don't like (because you didn't favor any of the other options).
Say we take the 1-2 rating system (up/neutral).
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10
Voter 1: 2 1 1 1 1 1 1 1 1 1
Voter 2: 2 2 1 2 1 2 2 1 1 2
Voter 1 is doing the game, as it were, or maybe just has a strong preference, while Voter 2 is going by general preference.
However, is anything lost if we allow:
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10
Voter 1: 2 1 1 1 1 1 1 1 1 1
Voter 2: 2 1.5 1 2 1.5 2 1.5 1 1.5 2
Voter 1 is still doing the same thing they'd be allowed to do in any rating system, with the same effect, and Voter 2 is expressing their preferences better. It's in a 1-2 scale, but this is just a rescaled 1-3 rating system (that is, up/neutral/down = 2/1.5/1 = 3/2/1).
I could very well have missed something, but if this is correct, then a 1 to 10 or even 1 to 100 (perhaps too clunky) rating system is always more informative than an up/down system, even taking cynical voting into account.
Speaking of trying to game the system, I remember one site had a 1-10 system and would divide down the value of somebody's votes during summation if they had a high standard deviation (since they are just voting high-low), but that might be a little rough, he he he.