It's not that bad, there are a lot of fun worldspells (apart from the Mercurian worldspell which you probably just forgot, March of Forest and Rally come to mind), others, while less fun (especially in multiplayer), can give you the edge by allowing you to use your civ's abilities to their full extent (e.g. Khazak and Grigori worldspells), nonetheless it's true that some are both weak AND boring, most have been mentioned before, Matzatl and Cualli, Legends, Revelry even seems a bit off lore-wise - I can imagine the Balseraph running wild and being "merry" (in their warped ways), but why should that suddenly make them work harder? - and I never found the right time to cast the Legion worldspell, it seems like a waste in the early game when you need slaves but have few military units and later in the game you have enough units but you don't need any more slaves (you never really need more than ~60/city since you won't be able to produce more than one unit per turn anyway).
And while we're at it, it would be really cool to get a pop up (with a picture if that's possible) whenever a worldspell is casted by any civilization, would make it appear more like an epic one time event rather than like something at best deserving a side note in Erebus' history books (" *³ Around this time the Dural increased their production by 100. ").
Edit: On Topic: Love the Illian worldspell, it's your lifeline after completing the Draw (doing that without Stasis in multiplayer is suicidal), but it's even more fun when it's used against you, annoying as hell sure, but that's what makes it fun.