I'm with thrud. This makes life harder on spellcasters, and (depending on that spellcaster's player's perspective on simulationism) less fun for the player.
Do spellcasters really need that sort of nerf? (Honest question. I've pretty much never run an RM game above 4th level, and that was 20 years ago...)
As I said at the beginning -- this was just some random musings... AT MOST, it might become an option down the road, but even that is not guaranteed.
And quite simply, where everything else in the game requires rolls and includes chances of failure (not counting fumbles), magic doesn't. If it isn't above your level, you cast it automatically, and personally, I think that might be a problem.
Rolemaster is and always has been heavily balanced towards spell users.
The idea is ok but you should always be able to cast spells at your own level or lower without risk of failure. As long as you take your time and don't rush things.
There is room to tweak... these musings were basically first draft of the idea...
Hmm.. if we double the level bonuses (which I am not sure would be a good idea), that would make the Casting Bonus be a 70 (an 80 if we consider that the stat is likely to be high enough to give a +20 bonus rather than the starting stat of 90's +10 bonus. -- maybe lower the base for the CTN from 20 to 10 instead.
Nor does my musings take into account the racial bonuses that might be had....
But the point still stands, right now, unless ESF rules are in effect, there is NO CHANCE for failure when casting a spell (like there is for failure in everything else!!!). You either cast the spell, OR you fumble (screw up so royally that you hurt yourself.
There is no in-between. Yet for everything else, you have fumble/failure/success -- magic is fumble/success only.
By the logic you use on magic users and spells, unless he fumbles, a warrior should hit his foe every single time, with the only variance being how well he hit, not IF he hit.
And a Thief should ALWAYS be able to pick a pocket and not get caught. etc....
(yeah, it is a bit silly, but it is just as silly to apply the same to magic users, IMO).