At least Wicker Man winds in and around the structure multiple times and fits in more. This is just sad.
Wicker Man without the theming wouldn't be a terrible roller coaster, but for sure a very weak GCI that everybody would shrug their shoulders about. It's the overall experience that turns it into a great ride.
Colossos however is a fantastic rollercoaster, with a very simple Out&Back recipe. Adding in a little bit of spice at the very end will still be an improvement because the ride experience usually tends to decline towards the end of the ride when the hills get smaller and smaller. Some fire effects definitely make for a better finale than nothing at all, and if I'm not getting the perspective wrong, it should be visible nicely from outside and the queue line.
To all people who are disappointed about this (which I totally understand btw, this is Merlin overmarketing at it's best), well how would you have approached this if it weren't for more or less strict budget limitations? What would you like to see in terms of additional theming? I could see another theming structure with fire effects inside the helix, but besides? You actually want to theme 40-50m tall airtime hills? There's only so much you can do to a layout that was created without any theming in mind.
Like, if we were talking about Balder, yeah, I would totally understand an argument like that. With it's multiple layers stacked on top of each other, that's about as easy as wooden coaster theming will get, and even though the entire surrounding area has received a major overhaul, nothing has happened to it and that doesn't appear to change in the future. But do people complain? Some do, sure, but not nearly as many, because Balder is still a great roller coaster and Liseberg is not run by Merlin Entertainment, which tends to make people more forgiving.