Well, my sentiments have been stated by ScherBr and I won't state again.
I will just add some points to that.
First, people are greedy.
So when you give them the option of 8 keys with 2 keys requirement, most of them will use all 8 keys.
Which will prolong repetitive gameplay, make it seems more like a chore rather than a privilege.
If I can find the silver lining between Jayle and ScherBr. It would be rather than 8 keys, it should be 8 chances to enter with only 2 counted highest run.
But as I stated above, it only makes raid a chore.
Second, you actually encourage unnecessary competition among guildmates.
We're actually trying to lessen the competition among guildmates to make it more of a community effort rather than a personal effort.
Personally I'm a pretty competitive player as long as it's within my convenience. If I no longer feel the convenience, I'll stop and just watch the world burn.
Because games are supposed to be fun, not frustrating.