Currently, the sp curve ranges from 570(1-2) to 100,000 (49-50). If the average mob the same level as the player gives 100 sp, then we are expected to fight 6 mobs to get from 1-2 and 1000 mobs from 49-50 (soloing). Now, if we were to fight solely 10+ level mobs (for the level gap cap) we would still have to fight 333 mobs for 49-50 (soloing). If we fight in a full party, we would have to fight 502 mobs 10+ levels.
Now that was grinding, but let's see what it's like when we do Guildleves. If we fight = level mobs solo on a leve, we get 50% bonus from Aspect. We would then only have to fight 666 = level guildleve mobs. If we solo 10+ level leves, at 50% bonus, we would have to fight 222 guildleve mobs.
The party scenario is different because of the leve-link bonus. The maximum bonus for partying on leves is currently 275%. In this case a full party would only have to fight 134 guildleve mobs 10+ levels.
The big problem here is that party leves are 3.75x better than grinding, which is a huge disparity. Furthermore, guildleves were meant to be casual content, since they have limitations, which means that once players are done they basically won't want to grind because of the disparity. What's even worse is that if a player misses the leve-link rush, they're kinda screwed.
Now, this post isn't so much about guildleves (which i am aware are being changed) as it is about the disparity between the bonuses granted during limited content, and the options that players have if they wish to continue beyond that content. I would say that any sp bonus granted (using sp from grinding as the base) should not exceed 125% unless such a bonus is unlimited (in which case why not just lower the sp curve?). That way, when players run out of bonus, they aren't seeing a huge dip in sp gain doing regular things. This would also be good balance for when fatigue is abolished because A) everyone hates it, B) it negates the ridiculous bonuses anyways, and C) you can get it in 2 hours in a good party.