Sounds like a clickbaiting header, but what I mean is that 9th level wizard spells, while undoubtedly the coolest, come so very late in the game series, one has to ask whether they are worth considering a part of one's spell arsenal. And whether it's worthwhile to design new ones. In pen-and-paper games, if the Dungeon Master allows very high-level parties, there may still be room for that kind of magic, there may be progress to Elminster heights, but in the Infinity Engine games we have a definite limit to adventuring material, even if it's technically possible to reach level 25 and beyond.
The dilemma is that, on one horn, there are some great unexplored opportunities and powers the toolset has the functions to represent, but on the other, if these spells are interesting at all, they immediately demand high levels from the designer to be balanced. An example at hand, I have an exceptional idea, even by my standards, that lets players capture and manipulate their past gameplay. It's almost through the fourth wall, functionally, but I can probably give it a convincing representation in the name of the spell, its description, look and so on. But I have no idea what level to assign to this spell so that it's actually useful for a long time through. I assumed the 6th, but now it's starting to look as powerful as anything in the 9th level - and if I make it 9th, I reckon I might as well not make it at all.
I wonder if people use those super-high-range spells extensively?