If it's like any other drop event ever, then all mobs have the same drop rate as long as they're near equal level to your character (ie: white/green, though I doubt you'd get penalized for taking on the stronger stuff).
A well equipped low level nuker or any character that can kill fairly quickly and never have to rest (orc fighters come to mind) would be ideal for the event.
during the last firework event, i had started a new orc shaman. he got a LOT more drops then my lvl 24 raider during the event. I noticed once I hit 20 (started the event when he was around lvl 12 i think) my drop rates declined.
maybe it was coincidence? maybe it was due to the fact that at lower levels I was able to kill more mobs more quickly too..
At the last pumpkin event, which was verry simmilar the drop rate seemed to vary more per hour then with any other factor. It seemed that if little people were on, for example just after restart the nectar (in this case pollen) dropped far more often then when it was very bussy.
Basically it seemed as if a certain amount of nectar was supposed to drop that hour, spread over the amount of mobs killed.
If this is true it might also very per area though, for example areas where almost no-one levels (like orc village area) might get alot more then highly camped areas.
I think Niennia is right. Sometimes I would log in and get 3-4 nectar per buff set, and other times every mob would drop it. I don't know if it was based on server population, or other factors, but it wasn't a fixed rate for sure.
Only problems with a low level nuker is footspeed, mana management and if you are talking D grade or lower, no Acumen stacked. But if you can find a good spot with plenty of mobs that respawn fairly close together, you should do well.