They aren't going to nerf Bard just to re-balance it all over again in six months. They didn't do it for Dark Knight, they didn't it for White Mage, they aren't going to do it for Machinist.
And no, it's currently preferred but a Dragoon-less comp with bard is perfectly viable. That wouldn't be the case if you suddenly take an extra 400 DPS away for Bard. Now any static running Bard without Dragoon is just simply dumb. The damage loss is so substantial, it's plain foolish to run Bard without Dragoon whereas that isn't the case now.
You do realize "meta" trickles down, yes? Monk is perfectly fine but you'll see groups take Ninja every time because "meta." A 6,700 rDPS Bard is dead weight when Machinist would be pulling in the mid 7k range.