I'm somewhere in the middle, Keith; I love the champion, and I love the micro-heavy battles the champion creates.
What I don't like is how ~grind~ heavy many of the nebula are. I really WANT to like all of the nebula. Some - Epsilon Erdrani and the dimension prisons come to mind - are very fun and I don't mind doing repeatedly.
Some, however, are basically "gear checks" as mentioned above (BTW I only have human and neinzul hulls, and my weapon unlocks are interceptors, paralyzers, and HBCs, so I think Ravenous Shadow is impossible for me right now). Gear checks as a gameplay mechanic are fine. The problem, however, is that they are gear checks that you have no way of knowing is coming, and nothing in the game to tell you how to prepare for them. If you walk into a nebula and you don't have all the right gear for it, it's time to reload a save.
Still, it's good to hear that I'm not just doing something horribly wrong and the scenario actually is silly hard.
To reiterate, Keith: I like the concept of nebula, and I really like some of the nebula. A lot of people are bashing on the whole nebula mechanic as a whole and I'm not really with that crowd. I'm just getting frustrated with the execution of a couple of the nebula.