See, I've ridden Wicker Man a lot over the years, and I'd say it's fairly consistent on the whole.
However, I will agree that inconsistency can be a factor. And I don't think it's just GCIs that are "moody", as you put it; I think it's woodies in general.
I may have mentioned WM being fairly consistent above. However, I have noticed that while it's always fantastic, there are some days where it doesn't seem to hit quite as hard as others. In 2021, I'd say that my September rides didn't seem to be hitting quite the same height of fun as my June rides (although they were still phenomenal, and easily 10/10 tier; WM doesn't vary much). And let me also just say that in April 2021, it provided what was quite possibly one of the strangest coaster rides I've ever had; it was a front row ride, and up to the final wicker man pass through, everything was fine and usual. But in that final pass through, the ride jolted me incredibly hard and gave me an absolute thumping headache. And I don't just mean a bit of brain rattle; we're talking a "Saw The Ride on a bad day" level headache. When I got off, I could feel my head pounding with each step I took away from the ride, and it didn't subside for a good amount of time after I got off. In 14 total rides on Wicker Man over the years, I had never had that before and I have never had that again since (and I've had 8 rides in various seats since then,; they've been pretty consistently fantastic, as well as pretty consistently smooth). Very weird!
I know it's not a GCI, but I've also found Megafobia at Oakwood to be wildly inconsistent based on my two experiences with it. In 2016, when I first rode, I was sat on the front row at the end of a warm summer's day, and the ride was flying; the airtime was awesome, and the pacing felt fast! Fast forward to 2019, when I rerode on a dreary morning in May, and it was a very different coaster even in the front; the front row ride was fun, but the airtime seemed notably weaker than I'd remembered, and there were numerous dead spots around the layout. And that's before I even get onto the inconsistency between rows in 2019; each row I rode in felt like a totally different coaster. Front row was my favourite row, and this was fun enough; not overly rough, with some fun pops of airtime. The middle was still not overly rough, but it just lacked sensation; the ride felt like it was desperately trying to give fun airtime, but couldn't quite muster it up. The back certainly had 1 or 2 more forceful ejector airtime moments that the front & middle didn't, but it was pretty rough, and I came off feeling very bashed about.
