The ONLY way this sort of matchmaking made sense is if the prizes were tiered as well. So, the 3.0M GP player with Revan / Traya / NS / CLS+3PO, etc. that finished 8th in their bracket still received better rewards than the 3.0M GP player that has three G12s and an army of G10s that finished first in theirs.
Why should eight players that narrowly focused their rosters be forced to compete for the same prizes that eight players that took a broad approach can receive? It's a form of welfare that we haven't seen out of the game.
But how do you define those tiers? The "fairness" switch flips - so that "narrow rostered" players are potentially paired with players with much higher "Raw GP", which you could argue in and of itself is fine, but only if the GA character pool is limited to those characters on which the "Refined GP" calculation was used. However, now your removing the ability for players to use characters they've developed, and we all saw how well that was received. In this model, there's a potentially massive advantage for longer term players with gobs of G10 players that can whittle down teams to clear a zone that "more narrow" rosters wouldn't have. Raw GP matters.
Finally, mods will still rule the day. One of the things I've seen in the plethora of "Wide vs. Narrow" roster complaints is that many of the "Wide" players think that gear is the end-all-be-all of GA, and while gear is extremely important, mods, matchups and turn order also make a big difference. Forgot to put an AoE on your CLS team, there's a 50k stealth team that can take out your 100k team multi-zeta team. Didn't stack enough potency on your zEP team? High tenacity Nest would like a word. Etc. etc.
I do understand the point about Ship GP vs. Character GP, but my understanding form the initial announcement of the game mode was that matchmaking takes W/L record into account. Over time, that Ship GP advantage could become a differentiator (think of how the forums would burn if 2 defensive fleets were required!!). We're still in early days.
Worst case scenario, you get 18 Mk2 mod salvage for just showing up. Nothing wrong with that.