You want MOC for two main reasons:

1) Counteract Force-on-Force

For my capped wizard I was finding that a number of my deaths were occurring when I was being stunned and then additional creatures would enter the area. I was fine with 1-2 critters in the room trying to finish me off but if a third wandered in before I recovered then my defenses weren't holding up. Adding 10 ranks of MOC (enough to counter the FoF effect of 1 additional critter) pretty much solved this problem for me.

Take a look at the circumstances under which you are dying and if a number of the scenarios involve critters ganging up on you then it may be worthwhile to add 10 or even more ranks over time.

Also if you tend to hunt a lot in war camps or other "swarmy" areas then 10 or more ranks of MOC may make sense anyway.

2) Increases the number of targets you are likely to hit on ball spells.

As a sorcerer I think you only have 1 ball spell where MOC matters (Balefire)? The 2 ranks you have should already make a fairly noticeable difference in number of targets hit in a crowded room on any given cast. If this is your primary driver for training in MOC I would say that at most 5 ranks would be needed for a lot of slpash benefit (and 2 is fine as well).

-- Robert

You raise your heel high, bringing it down solidly on a severed troll leg's foot!
The severed troll leg howls in pain, clutching its toes!

<<As a sorcerer I think you only have 1 ball spell where MOC matters (Balefire)?>>

Sorcerers also have access to Fire Spirit (111).

Starchitin

A severed gnomish hand crawls in on its fingertips and makes a rude gesture before quickly decaying and rotting into dust. A gust of wind quickly scatters the dust.

>Therefore, the "rule of thumb" is to pick up an enhancive item to provide a few ranks of MOC and avoid training it until you have reached cap and met more pressing goals.

that's pretty good advice.

I, of course, did not follow this intelligent route and got 10 ranks

Thanks! I tend to "bug out" if there are more than 4 critters attacking me. I've been hunting in the Citadel and the defenders tend to show up in groups that can quickly overwhelm me.

FI works pretty good, I fire one at a stunned creature then either clean up or make a hasty retrograde move to regroup my thoughts. Sometimes one or more will follow me and if it's one of the tougher creatures, I hit it with a focused maelstorm to get it to move on. Then I follow it around firing off MD at targets of opporunity to keep the FM running. It works surprisingly well because the creature will try to flee the FM and I am only in each room for a few seconds.

Magarven the Mad

I know one sorcerer who hunted camps with FI exclusively and he had 10 ranks of MOC just to stun more targets with it. Might have been a bit over kill but he rarely died that I had seen.