Have you been to this area recently?
You can not avoid the greaters as they're mixed in. The spawn is totally screwed up in that it is impossible to go around it without getting killed by the greater dragons or whatever other things are running about. There will be absolutely NO ONE at this spawn, no candles up, and there is a huge number of beasts other than what you're saying should be there when there isn't a champ spawn going on.
I go there several times a night, and if no one shows up to help, I usually leave when the spawn's level 3 or 4 spawn arrives, if any spawn other than Barracoon.
What you're describing is what happens when someone abandons a spawn in progress. Apparently, you aren't aware that spawns LOSE candles if not being worked (down to 2-4, depending if someone used Valor on the altar), and you can end up with a mess of the full range of spawn if someone leaves, because the stuff sticks around.
You can come to a spawn 90 minutes after someone took the candles to 12 reds before leaving, and find the place overrun with an ugly mess of level 1-3 spawn critters - for HOURS, if it's not cleared. As the spawns are never "off" except in the time (about 15 minutes) between boss death and start of the next (and even leftover spawn stays until the altar resets), that means you can have crap thicker than most invasion events.
IF you can get any existing Greaters from the natural spawn of the area, off to the sides to where you don't have to go near them to advance the spawn, Valor is no harder than Humility - perhaps even easier, as the terrain has less blockers, and the altar itself is in an easily defendable "base", where a party can station a couple of healers to rez people that die outside to the spawn, and are able to take out the spawn that actually pops in near them.
And, yes, the greaters are mixed in, to start. But if your character has magery or hiding, you can escape by having them chase you away from the altar for a screen or two, outdistance them, hide/invis, then circle back around out of their line of site, to where they are less likely to wander back in. Not perfect, and only legal if you keep them inside the valor spawn area, but easy enough. Most often, 1 or 2 greaters by the bridge is the result of people RUNNING AWAY from them, to recall out once they get clear of the spawn interdiction zone.
Why don't you try getting some friends together, clearing out the valor spawn, then actually note where the greaters and other critters that don't match the spawn type just finished actually are, before you make snap judgements of what the area's spawn is really like.