Have you considered perhaps that it isn't the difficulty of the stratums but the fact you need to improve? Ultimate Wildwoods if fine, even without piercing/shadow/poison resist I got through with it with sub 5 deaths while bombing with negative poison resist, I'm quite certain many of the players whom are both better than I and likely better equipped could do it even easier. It's challenging no doubt, but that's the entire point of the ultimate stratums, they're for people whom have mastered and are bored with the current tier 3 content; if you're finding them too difficult you probably aren't ready for them.
That being said I will agree that the room in UFSC with the outer spike ring, a totem and a Slag Guard is just poorly designed, especially given the guard can simply pin you against the spikes and there isn't a way to prevent if you've got any degree of lag. UFSC as a whole isn't that great in design, some parts are too easy and the odd spikes in difficultly are mostly due to cheap hazards, it essentially exemplifies all the problems the existing fsc has.
I don't think the new Royal Jelly is meant to be an "Ultimate" version, but rather a refined version of the current tier 2 boss (that's why they gave us tier 2 gear).
As for the other things you said, yeah, I agree more or less, although I'd personally like the Roarmulus Twins to be harder, and I really, really dislike Snarby.