If spell making isn't in the game, I will be very, very sad. My most entertaining characters are mages, mostly because of how insanely customizable they are being able to both make spells, and enchant your gear exactly as you want.
I don't know how capping would affect anything, as I've never come across the issue. But I'm going to assume capping is bad. Don't hard cap, at most soft cap. The more you can customize your character the better. I know I've gotten a little annoyed with how quickly i could max out a stat, and wished they'd go higher. But then again, mods can solve these kinds of problems fairly easily.
We still don't know enough about how skyrims new systems will work, but, if they dont get magic right in Skyrim it doesn't just kill mages, it kills all the hybrid classes that people have grown to love in TES like spellswords, and night blades. The freedom you had in TES to play diverse and unique hybrid classes was a big thing that you simply did not find in other games.
9/10 RPG's either force you to be a mage/rogue/warrior or had very weak hybrid options. Only TES allowed you to play a character that seamlessly blended any magic skills with any rogue/warrior skills in any combination you wanted.
Trully, if they don't get spells right, they will destroy more than just archetypical mages.