In one of the interviews YoshiP did, they talked about how "MCH DPS is actually not bad but the job is hard to play so people aren't reaching that potential", something like that.
I don't really agree but that's not relevant here, I guess in the eyes of the devs, maybe the timing fix for the display of the 1-2-3 procs would fulfill that requirement of 'increasing sustained DPS output'. You might say well that's not a real buff since it's only helping when assuming suboptimum play - I agree, but that's just what was said.
That, combined with the very real buffs to Gauss Round and Hypercharge would fit the bill for the kind of buffs they had in mind I guess. Maybe not an amazing amount of buffs (the Hypercharge buff is seriously pretty good though), but still buffs nonetheless. Don't forget they might view the TP cost reduction as a 'sustained damage increase' too, even though running out of TP is almost a non-existent problem in practice (who knows what Midas fights are like though).
Edit: Found it,
I have to say I blame the interviewer for leading him on by saying "So MCH DPS is pretty good huh", /eyeroll. If he said it was bad, we'd at least get to see Yoshi say something like "No I think they're OK" and give a justification for why he thinks so.So we can have peace of mind for now (laughs). I understand that you'll be increasing the DPS for Machinist, but the DPS can be pretty high right now for players with good command of the job?
Yoshida: Yeah. However, only a small fraction of people are there right now, so we wanted to make some adjustments to operation of the job to make it a bit less difficult to get that return.
Of course, but part of the image of Machinist is that it is more difficult to play.
Yoshida: The original idea for Machinist was to create a job where operation was complex, but it could be strong in the hands of a skilled player. Compared to bard, it's a step up in difficulty and intended as an expert job. However, when players look at a job which has a more complex operation than other jobs, really the only thing they are looking at is how much DPS can it deal.
And because of the difficult operation, it may not put out as much DPS as expected.
Yoshida: In this difficult state, many players think "machinist is weak," and we want to make adjustments to get rid of this negative impression. However, it wasn't really a major adjustment.