Forgive me if this has been stated elsewhere... I've never seen it on these boards, and it's important (at least to me), so I figured I'd share.
I noticed a pattern in my SP gains which affects overall SP earned. The amount of SP you receive for each mob is *directly proportional to the mob's HP percentage* as you initiate battle.
That is, consider mobs that are close in proximity that aggro on sight, but are not partied. That is, when you attack one, its display name will turn the color red while the others remain yellow.
Naturally, you'll try to AoE the other 3 yellow mobs while focusing on the red one for survival purposes. As we already know, you only get SP gains for killing "red" mobs or parties of mobs. However, I've noticed that in employing this AoE strategy, the SP gains for the rest of the mobs was diminished.
Upon further inspection, I noticed the pattern. Let's simplify the scenario a bit to demonstrate the mechanic. Say you run up to two identical mobs right next to each other that are not partied/linked. You do an AoE ability (Fire, Pierce, etc) and at the instant you kill the primary mob (i.e., the one that was 'red' first), the secondary mob has exactly 50% health of the primary mob. When you engage the secondary mob, its name then becomes red. You take it down, and the SP you earn will be EXACTLY 50% of the SP you gained from the first mob.
Try it yourselves.
This appears to be the way the system is currently working, and it's one more reason why it's very broken. There is no incentive to AoE mobs now, at all, unless they are partied.