Bard's problems in current content stem from how weak they are when they can't keep their DoTs running on any targets. Each time they have to either apply their DoTs anew, or forgo them entirely in the case of an add that isn't going to last very long, they lose out on hundreds of potency. Additionally, Flaming Arrow gets undermined by mechanics that cause the boss to be moved around.
Making the DoT/FA ticks stronger doesn't really change any of this - in fact, it makes the gap in DPS between a Bard-friendly fight and a Bard-punishing fight even wider. While raising the ceiling damage by 5% or so will of course raise the floor damage by a few percent as well, the goal should have been to raise the floor by 6-8% while ideally only adding maybe 1-3% to the ceiling.
And if SE actually took the time to understand how 3.0 Bard works, there were at least a few relatively obvious ways to make strides towards that goal, and a lot of room for creative solutions as well. Chief among the options would have been a duration compression on Flaming Arrow, better initial-hit damage on Windbite / Venomous Bite, significant oGCD attack buffs, an extension of Straight Shot's duration, addressing the WM vs. River anti-synergy, some way to get consolation damage when DoTs are down, or a couple other things.
But the Blunt Arrow change is the only thing on that list that they actually did - other than that it's a bunch of fairly thoughtless "we don't know what to do so let's just add a little bit to everything" buff. (Granted the song changes make a lot of sense, but that's sort of a separate category that doesn't take much of any class-specific knowledge to grasp)
If A9-12 roughly resemble A3, A4, A5, and A8 in style (as in, if A1-2 and A6-7 are true outliers), then the final numerical result of all this could actually be okay. Bard will be a little better in a fight or two, Machinist a little better in a fight or two, and they'd be even-ish in a fight or two.
But now the onus is on SE to actually produce those suitable fight designs - while also not botching BLM vs. SMN - when they could have had more freedom if they targeted Bard's weaknesses for buffs rather than just making their strengths even better.