For now, may as well go with the "band-aid solution" if it makes people happy.
I personally have an idea I feel will be much better - based on why EI got buffed to it's current numbers in the first place - but I think a bunch of people are too caught up on the 75*rank option to care, to the point that it's even been said to discuss other ideas later. As such, I'll leave it in a spoiler tag for those who are unwilling to humor the idea of anything else.
Why Ether Invitation was Buffed:
At 50*rank, capping at 250 BEFORE applying any modifiers (Def/Res/Hunted/etc,) it was honestly pretty freaking pathetic most of the time, unless you went around doing things like stacking Fallcall and Holy. This is due to how the cap was BEFORE any modifiers. And that's the entire problem, isn't it? The modifiers. They allow bypassing of the cap, since the cap is applied BEFORE modifiers. My original suggestion was always to re-organize the order of calculations... but Dev just wanting to crank the cap up simply opened the floodgates for abuse while completely ignoring the original problem completely.
My proposal:
I say, we put it back to 50*Rank, but apply the cap AFTER modifiers. Missing 400 HP going up against 50% DR? You do 200, not 125 due to the initial cap. This means that no matter what modifiers you have, you can only do 250 maximum, regardless of if you're pitting 250 missing HP against 0% DR or if you're missing 1000 HP and going all Fallcall Holy on someone.
My plea to Dev
Seriously, Dev, these "capped" skills are the absolute worst and always have been, due to how the cap is applied before any modifiers. I remember back when board shaker was new: I had a bodyguard equipped, went to go test rank 1 against some Jammer Deltas who had 22 res... and did THREE damage, THREE, because the cap of 25 was applied before the 22 res since Def/Res were flat reductions back then.
For the love of Kraken, Huggessoa, and Ryart (but not Mercala, that bitch owes me money) any time one of these must exist, please make the cap AFTER modifiers.