This (Force of Will) is the big thing.
All tribes can play 12lords, so all are equally* (*I'll get to that) capable of getting out of red sweeper range. The fact that you have a lord at 2mana isn't such a strong argument when you consider that the other two major tribes can cheat on mana more often.
The big difference is the fact that you have access to a disruption suit that is beyond any of the other tribes. They can splash for black and discard, but this slows them down and it usually has to be moved from SB to MD; weakening their gameplan somewhat. You, on the other hand, can generally play your disruption for free, which keeps the opponent on a clock and you in the lead. I'm a big believer in the whole tempo angle of Merfolk I alluded to earlier.
Just to clarify though, being able to stick down 2 lords is mute when they can kill one and then sweep the board. It's harder, but can be achieved (and it may delay them a turn which is all you need.....). If playing 12 Lords was the key, then Elves would have more success.
The difference is that Merfolk can totally avoid this by countering either of the spells. It doesn't matter if they play Volcanic Fallout; you just counter the other kill spell. This is the big difference between the three tribes.
I'm not dismissing the importance of 12 lords, it is the reason players should fear llanowar elves. I just think you overstate their importance when countering damage based removal, as I feel the disruption is more important.
Everything else, I concur with :-)

