Those charts are pretty accurate (although they are for the A-model of the Hellfire, the later models use a flatter trajectory to help keep them out of clouds when there is low cloud cover). The Hellfire has a capability of climbing above a 1000 ft obstacle if fired from 1500 meters away in LOAL-HI mode, so that's not a very steep climb, just a little over 20% (which of course is still pretty steep, but maybe not as much as it looks like when viewed from behind where it looks like you're launching a satelite or somehing :) ).
Relativly, but keep in mind that it is much steeper toward the end of the flight, as it dives toward the target. It hits the target in a fairly steep dive, which is significantly less armour to penetrate.
We had some interesting discussion around this when I implemented the Hellfire flight trajectories for EECH last year, check this thread: http://www.simhq.com/forum/ubbthreads.php?ubb=showflat&Number=327386&fpart=1
Pay particulary attention to AlphaOneSix, he used to work on the AH-64A.