How about a compromise?

[Lyrinn]

Make Coil becoming easier optional. Players who beat it on original difficulty get an achievement and/or token(s) for special weapons a la EX. Players who simply want to get to the next stepping stone can opt for the echo buff.

Casual players who want to progress can progress.
Players who want to feel proud of their achievements get a special something the casual players can't.

Done.

Then the casual players are going to cry about not getting the tokens for the special weapons.

How so? If they want it, then they can beat Twintania on normal difficulty. The option is still there. By making the nerfs optional and giving you the freedom to choose (similar to normal mode and hard mode, or in this case, "easy" mode and normal mode), you cater to both groups without alienating either. You don't hear people crying about not being able to get the EX weapons.