well, maybe i see it a little...differently 'cause i'm using dark team, but i don't think it's all that bad.
i mean, for now medusa is my main eidolon and she boost 30%, so even if dullahan's attack is lower, she can boost the attack by 40% and also HP.
this axe can be held by arthur, and really, who will use a soul with dark weapon outside dark team? by the time i'll be able to use my yata/jorm i'll have to wait at least 8 turn while arthur can use her burst turn on the very first turn and give the attack debuff.
and that aside, the skill level of my weapon aren't as high so the gems and grails i can get there may help me with that.
also a small amount of jewels in gacha...
but, like i said i may think that way 'cause i'm actually using dark team XD