Well immersive health has been done in games enough by now, what with red edges and heartbeats. So getting rid of the health bar is possible. Theres also Fatigue which could use panting. Im not sure how to do Magicka
, maybe you start to black out or the more burned out you get from magic use(running out of magicka) there could be stuff like... the world starts to loose color, like everything starts going black and white. Or get rid of magicka altogether and have spells cost Fatigue instead.
Yes I wondered about the fatigue bar, as TeS already uses it for impact on magic.
In Morrowind you had it increase percentage I believe ( it's been awhile ).
In Oblivion it lessened the effects, time or damage dealt.
So a mage is thrice afflicted with both magicka and fatigue rather than just fatigue and health.
Two examples of fatigue being used, the first I'll use is not the best however.
DA:O: in that they just call it magic / fatigue, same thing just different colour on the bar the characters both mage and none mage use.
The second beter example to use as the character generation / leveling is far more similar.
Is Arcanum: in that you had fatigue as well.
Every move, attack both dealt and taken, spell cast.. etc would effect fatigue.
Once your fatigue reached 0 you'd pass out untill you raised it.
A tad extreme it would be in TeS however.
Although since potions are more available, potion gulping is frequent and is penalised whether you're a mage, fighter, rogue, or mix of any / all.
I don't see it being anymore extreme than combat use in Oblivion tbh with minor tweaks.
The last way would be cool downs.
Cool downs are in I think at least for dragon shouts, modders have used similar effects by tagging scripted effects before.
An example would be like a shield that gives X for Y, as long as Y runs X can not be cast again.. bad example I hope you understand what I mean though.
Honestly I think the magicka system we have in TeS is the best for TeS.
Or a tweaked Arcanum one maybe, I would like to try a modders attempt at these though.