Keep this in mind when referring to magic skills:
SHOOTING
Skill (15) + Agility (12)+ mods (+4) = 31 dice.
this is pretty much the max.
From this, Damage is determined.
MAGIC:
Spellcasting (15) + Magic (unlimited!*) + Mods (unlimited!**)
There is no max, as magic has no upper cap. And since magic has no upper cap, Foci have no upper cap.
Damage is either determined by Net hits (force), OR force + net hits.....
So, damage potential is only limited by the force, which directly relates back to magic... thus unlimited.....
There is a reason mages are called "Karma sinks" and the nickname for the game is "Magicrun". The only thing that limits a mage's power really, is the karma available in a game. IF your game goes on long enough, the awakened in the party really start to outstrip everyone else in the group.
What good is the samurai in combat when his limitations are his weapons or his body compared to my mage that can easily throw Force 30 fireballs, hitting every thing within 70 meters for an average of 42p -15AP (if I buy successes), with only 2 stun damage (again if I buy successes)

Granted, I have over 4300 karma invested in my character which is vastly more then most players get to (I know of only 2 others on these forums who are not in my group), but it doesn't take that extreme level of karma to start to notice it.
Spells.
Spirits.
Rituals.
Alchemy.
Enchanting.
All ways to power, that are dependant on the magic stat in one way or the other, which essentially makes all the magic skills open ended in power and utility.... and you want to boil down this "karma sink" to fewer skills, allowing that power growth to happen quicker?
If you want less skills in your game, house rule it. That is what house rules are for.
But be careful when you start toying with the mechanics of a game, more then a few GMs have come here whining for help after their house rule Fubar'd their games.....