I don't know if this has been suggested before--sorry if it has--but I just randomly got an interesting idea for combatting RMT.
Here it is:
NMs are known for dropping items unique to them. For every one of these NM-unique items, each character has a modifier that affects the drop rate for that item. This modifier ranges from 0 to 1, and defaults at 1. Each time you kill a NM and get the drop, your modifier for that item falls by a certain amount, say 10%. Now, every item that can drop from a mob has a base drop rate. The actual drop rate, though, is going to be this base rate times the average multiplier of everyone who established hate on the mob.
Here's a few examples:
A, B, and C are in a party together. They are fighting an NM named Mobber that can only drop one item, Item X, and it has a base drop rate of 10%.
1) If this is the first time A, B, and C have ever encountered Mobber, then their average modifier will be 1 ( [1+1+1]/3 ), and the actual drop rate will be 10% ( 1*10% )
2) If A, B, and C are RMT and have killed Mobber and got the drop 22, 17, and 30 times respectively, then their average modifier will be 0.1025 ( [.9^22+.9^17+.9^30]/3 ), and the actual drop rate will be 1.025% ( 0.1025*10% )
3) If A, B, and C are casual players who have killed Mobber and got the drop 1, 0, and 6 times respectively, then their average modifier will be 0.8105 ( [.9^1+1+.9^6]/3 ), and the actual drop rate will be 8.105% ( 0.8105*10% )
Now, the modifier would have to slowly reset so you aren't permanently penalized for killing NMs. Maybe .25 a week? People need to be able to help their friends kill NMs too! Haven't fully fleshed out all the possibilities here, but you get the point. Bonus points for anyone who has an idea how to implement this in a way that maximizes the reset for legitimate players (helping their friends and whatnot) while still preventing RMT from just going on a circuit and killing a new NM every couple days or something.
Anyway, doing this will prevent the same players from monopolizing the drops for any NM. The % that the modifier drops for every NM kill could be adjusted on a mob-by-mob basis, too, to prevent horrible drop rates on NMs that normal players might need to kill often. It might even be zero for instanced NMs, because there's no worry about monopolization there.
Edited to look prettier ha
Also edited to take TandoPandemonium's positive criticism into account :P
And to take Twangaz's excellent time-reset idea into account (twice, had to clarify it)
Edited, Mar 20th 2010 5:27am by Morsmorde