Well the nice thing about "tension" is that it would measure the magnitude of active indecisiveness without revealing the actual vote count; this way you could get feedback prior to voting or considering without revealing the raw votes.

Examples:

++	--	Total vote	tension
100	5	95	low
10	5	5	low
5	100	-95	low
5	5	0	low
100	100	0	high
20	20	0	medium
50	20	30	medium-high

Another phrase for "tension" would be "high interest, controversial".

Matt

Update: grammar, clarity tweaks