It amazes me, though...somehow, it's OK to build a dam and flood an area the size of Massachusetts, then allow powerboats on the resulting lake, but putting in a few pieces of metal into a cliff is a mortal sin.
Actually, the rule actually originated from the above. The lake shore is mostly slickrock. A lot of boaters apparently figured out that taking a drill and a few climbing bolts was a good way to secure a powerboat. Bolts started popping up all over the place along the shore and thus the ban started. GCNRA has been the scene of "bolt wars" among canyoneers and other groups as well. Long story though.
Oh yes...I'm not worried about finding enough technical challenge...it's more about diversity of scenery (tower one day, canyon the next).
You will have plenty of diversity, from sub alpine on Boulder Mountain to scenic, but barren deserts. Indian Ruins and slot canyons.
Some of my favorites are as follows:
South Fork Choprock Canyon
Neon Canyon
40 Mile Gulch and Willow Gulch
Davis Gulch
Coyote Gulch
Peekaboo, Spooky, and (especially) Brimstone Canyons
Calf Creek
Boulder Creek
Death Hollow is good too, but choked with Poison Ivy.
If you want some diversity, Boulder Mountain is cool and forested (probably buried in snow when you will be there). Fiftymile Mountain has many Indian ruins and spectacular viewpoints.
It's hard to find a more beautiful place than the area around Escalante. Maybe places like SE Alaska, the Southern Alps of New Zealand, or parts of the Himalaya may come close, but the scenery is completely different there.