So for those that don't know SP from kills has two determinants:

First the monster's rank is weighed against your own (not the group as a whole). SP is scaled depending on the difference between your and the monster's rank. It scales up until the difference reaches +10, at which point you will not get more SP from a higher rank monster.

There is also seperate SP classes divided up by monster types that determine the maximum SP you will recieve from each kill. Coblyn types seem to give the least SP relative to monsters of the same exact rank, next up is dodos/goats and other somewhat weak monster types (less than 300 SP), wolves/mongrels seem to have a higher tier (300 SP in a duo). The second highest tier is Peistes, Efts, Floating Eyes, Raptors (450 SP in a duo). And Drakes and Blasts occupy the highest tier that I have found (600 SP solo). I'm probably missing a few tiers but you get the point.

Personally, I feel that SP should continue to scale above +10, why? Because it is trivially easy to duo up to +10 heck even at +12 it isn't much of a challenge. What does this mean for larger groups? Well in parties of 3 or more, basically every encounter in this game is a snore-fest at the highest SP you can get. (As a side note, the CON system in this game is worthless in parties, because even in a duo with an equal ranked person the rank at which monsters con 'Green' is already 1 or 2 ranks above the +10 at which you gain max possible SP)

Also on the second point about SP classes, I would like there to be more monsters classified in the top two tiers. I don't care if SE has to make the monsters harder to be placed in those classes, as it stands the game could stand to be harder. Right now the SP difference between a 55-59 rank range Snowbuck Stag and a 55-59 Grass Raptor is over 150 SP. It isn't so much harder to kill a Raptor to make the Stags warrant such a drastic reduction in SP rewarded. So either make the lower tiers somewhat harder and bring up their SP tiers, or maybe readjust spawns to include more of the Peiste/Raptor/Eye tier mobs because at the moment there are very few camps for these, and other than say a few choice Eft camps and the Grass Raptor areas the respawns are so bad that they can't even support a PGL/ARC duo for more than one sweep.