You don't really have any business getting into the minute details of another character's secondary stats in anything outside of EX and Savage. A bard needs Weapon Dmg, then Dex, then Crit, then the rest is min/maxing for limited gains. SE has already done enough damage to reduce the impact of secondary stats. Yes, they should make some sense, but the gear will make "some sense" as long as it is bard (or MCH) gear. DET and Skillspeed aren't that much different as in weight that you should get heartburn over it. I don't even think Accuracy is a factor in roulettes.

The skillspeed difference you are worrying about is not going to effect the dps more than a couple percent. Of all the things that can contribute to poor dps, this is in the weeds. There is no need for SE to devote any time on it.