Everyone is following the Celestial template that the top level spell would be 68.
How about a little twist on this idea to make the final three levels more interesting. (Assuming KI raises the next cap to 70).
The level 68 spell would be whatever KI comes up with, whatever type that may be. Upgrading an existing one, an augmentive spell, whathaveyou. Standard difficulty for a level 68 player. But this would not be their uber spell.
At level 69, there would be an extremely difficult solo quest to get a pre-cursor spell/card for the ultimate level 70 spell, which of course would be your most powerful one.
The uber level 70 spell (solo) would be impossible to get without this level 69 spell/card, but super easy if you have it. The one thing that keeps popping into my mind for 69 is a special card enhancement for the 68 spell.
So you enchance that level 68 spell with the 69 card, and it will pretty much guarantee that you will breeze into level 70 and know you have already done the hard work to get your most powerful spell.
After you have completed the super-difficult level 69 quest, you could always get another 69 card from the quest guy in case you fail on the first attempt at the level 70 spell.
(Note that this 69 card would have an influence only when the enhanced 68 spell is used on your school's 70 spell boss. I.E., if you enhance your 68 spell with it, it wouldn't have any effect on anything other than that one boss. So each school's boss would have to have some unique feature that is countered by that unique enhancement.)
Finally, the last boss of the world with the raised level cap can only be beaten by people with the level 70 spell.
I figure it would add a little more excitment about reaching the final levels, and an interesting design challenge for the KI team. I like the idea of an anti-climax in which you may have to try over and over to get the 69 bit, but once you are successful you will have a nice easy-to-get super reward awaiting you when you level into 70, instead of just an XP cap.
No, I have no idea what kind of statistics the 68 or 70 spells would have. I am not inclined to try to examine all the classes to find what may or may not be balancing without being paid to do it. (If it was my job to do so, getting paid to do it, I would greatly enjoy it and indulge deeply to come up with really exciting stuff. (*hint hint KI* :-) )).
