I'd rather see dot size, bigger the lower they are, then I know 'TARGETS HERE!'

Or alternately:
below 10k dot
10-20k a line through the dot -
20+k, a + sign instead of a dot.
Good for us colorblind folks too.

I'm really torn on this because on one hand, dar has some kind of indication of altitude, on the other hand it could easily create a world of running altmonkeys, which I would not like.
Wiley.