Pre-buffed gear would be something Id want to see and maybe 1 more loot per boss.
Then through in Valor vendor that sells flasks/best stat foodbuffs/enchants things that are needed as raider.
If they start giving out better items than you get from 10man, ohwell im not gonna bother with finding or making a 25man guild. So Im just gonna drop the game.
No shared lockouts? Oh god. So new raid appears, lets do LFR 10man and 25man. Please no. I don't want to do the same raid 3x a week just to stay competive.
25m really needs something, but if that something is getting gear that is just plain better ilvl than 10man's its gonna be a slap in the face for most of the community.
You just can't tell people that hey now 10m drops the same gear as 25, but you only get less -> everyone goes 10m cause raiding with friends is soo much more fun than 9friends an 15 randoms. Then after few years, you go back and tell everyone to go find 15more randoms if you want the best gear possible.