My assertion, is that if only the best items in the game drop in mp10, then it forces people to play mp10, and it has no longer become an optional difficulty.
First there needs to be an agreement amongst blizzard as to how long it should take to kill an elite pack at a certain number of dps. If it takes 10 minutes to clear an elite pack on mp10 @ this number, and only 1 minute on mp1, then mp10 needs to drop 10x the xp and loot as mp1. These arnt exact numbers but just an example for easy figuring.
Best items should be available on every difficulty, I think everyone who has suggested improving item quality has said the same. Here is what I said:
2) Make average quality drops in each monster power level more commensurate with expected player gear quality. The possibility of getting the best item should be available on all Monster Power levels, however, the possibility of getting a horrible item should diminish as Monster Power rises. Players would not be forced to play higher MP levels because they get faster kill rate on lower MP, thus more chances at a good item. But playing higher MP is still more rewarding because you get less junk and typical drops are more commensurate with your gear level.
This could be a replacement for the +MF/+GF scaling currently given
The key thing that is different from your perception is that the best quality items should be available no matter what MP level you play. The thing that changes is not your chance at getting a good
item, it is your chance at getting a bad
item. As you increase MP, junk should diminish. The reasoning is simple: a highly geared player is guaranteed to have no use for a low quality item, but a starting Inferno player might
have use for a low quality item. In both cases, players are getting items that they can use. As you get better gear, you can improve your gear drops in either of two ways:
A) Continue grinding low MP for more chances at good items (due to faster kill rate)
B) Challenge yourself with higher MP. You will get fewer items due to slower kill rate, but those items will be more likely to be worth the 1 second to identify. This is an option to challenge yourself with the game rather than grind with the game. Both options give the same results, it's just a choice of grind versus challenge.
It basically turns the MP question into one of quality versus quantity. For the outlier item of extreme value, both options are valid paths to reach it. If that perfect item roll is a 1 in a billion chance roll, are you better off getting it by trying to roll a billion times by killing tons of things, or to change those odds to make it a 1 in a 100 million chance, but only be able to get 100 million rolls in the same amount of time. That is up to the player. Monster power should be the thing that enables that choice. In 1.05 it is not the case, MP0 is better for all player, for all situations, for all purposes. There is no choice. MP0 is just better.