It turns out that one Thornhope instance was what was also causing the "epic books go one way, landscape quests go the other" problem as well-- the landscape quests that would have followed the epic into Fangorn were locked behind an impassable checkpoint. Looking at the forums, I gotta wonder just how many people will never meet the ents and the "OMG all the FEELS" story of Oldbeard and his little bird, because they can't get past Thornhope and give up trying after five levels have passed. (Dammit, a MMO shouldn't make me go all wibbly!)
Anyway, in Fangorn, I was finally able to switch back out of the blue spec for yellow against normal foes (orcs, bats, huorns), although I still needed blue to go up against spiders. Finishing up Fangorn and the last of the Snowbourne quests was enough to get me up to level 90, at which point I trundled back to Wildermore and hit the auction house, where I picked up the level 90 crafted gear-- the stats of which were literally double or better than my mid- to high-80s gear.
Welp, I'm OP again. O.o But if I have to choose between the two, I'll take OP over incapable any day. I can create my own challenges if I really want to-- but I can't ratchet down the difficulty if it's off the chart.
So I'm back traited to yellow, AoE-ing my little champy heart out. My war-steed has hit his maximum level  and I've cleaned out all the backed up quests that I just couldn't get through before. Even Hytbold is starting to cheer up as I make incremental improvements to it, although I think I may have run out of places to find quests for it and will have to circle back if I want to finish it off.
Of course, there's an update this morning, and who knows what that will do? Supposedly champions are getting buffed, especially in the red line, but as I'm all twinked out for yellow (and find red to be kinda dull), the effects might be minimal on me. We'll see.
 Making me worry that I'm going to have to "deconstruct him" and get a new one in the not-too-distant future. O.o