Looking through wiki, aside from "axe weapon skill" type evoliths, the whole system is looking pretty useless, with a whole 2 evoliths that look to be of any real use: dark magic recast, and physical blue magic attack.
The dark magic one may be of use on the great sword, or even the lolstaff if it can be paired with 1 or 2 other awesome things, but the blue magic one is what really caught my eye (and the only one that looked of any use when I first saw the evolith .dat list).
Since attack has absolutely no bearing on physical blue magic, I can only assume that it somehow directly effects the physical spell mods in some way, which is pretty *** sexy. Whether or not the Concordia can be etched with the right size and shape slot is yet to be seen though...
Anyway, with "great sword weapon skill: something" on the great sword etc. these do have potential to be extremely good weapons, but none moreso than the Concordia for blu, depending on what can be etched onto them.