I said this before but the insane tier should clear the whole map, legendary tier clear half, epic clear a fourth etc.
Thats actually an interesting idea. Having it % based (of all territories), would make it much more useful.
I suggest the following %'s: 0.5, 1, 2, 4, 8, 16, 25 .
While still useless at low levels, and at the end of a level, it would at least have some use. The official time estimate for a level (unascended) is about 20 days on average, so on rare (4%) you could unfog the entire map that way.