My VPS Node has been running since the DDos war and my motivation is not forging rewards....my motivation is to keep Nxt running...period.
Sure - of course there are probably quite a few running nodes whose motivation is not forging - hard to know whether or not that is the majority (perhaps being able to work this out might help with the decision).
I am guessing that a reduction from 1 to 0.1 should at least provide a good way to "get an idea" how much a "further tenfold reduction" would affect the network.