I think some people miss the point of what an idea is. An idea is by no means a complete concept.

I do like the idea, although it would need considerable refinement. I'll throw a few more ideas into this.

The most important part would be reducing SP awarded in relation to your current rank against the camp suggested ranks. This would be off-set by adjusting the star difficulty. Something like a reduction of 5% of base SP for each rank above the suggested rank of the camp (so a R40 would get 50% of the SP a R30 would at a R30 camp) with the addition of +10% base SP for each star of difficulty. With this, a R40 doing a R30 leve on 5star difficulty would get the same as a R30 doing it on 1star. It would keep it more balanced and make people head to camps more appropriate for their rank.

There are already time and difficulty bonuses in leves in the form of additional gil rewards, so I don't see that being too much of an issue to add a little bit of SP like the gil is added. I would, however, make the additional SP negligible like the gil is. Even making the additional SP the same as the current additional gil amounts would be good.

I'll push another idea in here since it would become applicable if SP was based on the leve instead of the kills. The exchanging of old leves for when acquiring the new leve could increase the SP reward of the leve. It currently only increases the gil rewards, so I'm sure it could be put to more use.

Pushing another idea which could be applied if your suggestion were to be implemented: reduction of SP reward for each consecutive time you take that leve. ie. taking the same leve every time would reduce the SP reward by 5-10% each time you take it. Think along the lines of narrative "you killed wolves for us recently, so not as much of a problem at the moment. If you go kill more now we'll still reward you, but with less SP". This would promote taking different leves each reset.

And in the case of failing a leve, knock 10% SP right off there for each time it is failed. Simples.

I'll leave it at that. They're ideas that no-one is likely to ever read, but I've given them at least.