Machinist main here: I think there's some good, but I'm on the fence right now.

Since SB came out, there's been a lot of debate on whether it was intended to stay between 50-95 Heat or if we were supported to line Wildfire up with Overheated. I think the changes make it clear what's intended, and makes it more worth it to try and pull off (20% damage over 10% damage) and less punishing to get wrong (2 second recast on GB vs 10 seconds).

Increased heat generation from Flamethrower also makes it easier to Overheat, though I would have preferred 4.0's heat generation (10 from heated shots, -10 from QR, more frequent Cooldown use)

Increased HS duration means we only refresh it once a minute- Small DPS increase, since it's our weakest weaponskill.

Lowered CD on Dismantle is also nice, but the timing on it is still really tight- It only lasts for 5 seconds, which makes it not as effective as it should be in some instances. (Susano EX- Every Ukehi after the first goes off 3 times, but you can only really mitigate 2/3 hits with Dismantle.) A duration of 10 seconds would be very helpful.

These changes aren't bad, there's a lot of convenience here, and Overheating being worth it now returns some fun/challenge to the job, especially after a lot of people (myself included) felt like 4.05 made it way too easy with how slowly Heat was generated. But...

Bard still has bigger, better utility, and I'm not totally convinced yet that these changes will be enough to give Machinist an edge over them when it comes to DPS. I don't think this is enough to deal with the stigma MCH faces in groups right now, but I'd need to play it for a bit before I can speculate on what other changes it needs going forward. (My guess for now: Probably some potency buffs, and/or raising Hot Shot from +8% Damage to +10%)