General impression is that BRD and MCH sort of switched places right? BRD went back to non Bowmage 2.0 and MCH sort of took over a similar play to 3.0 BRD. Those were just the initial impressions I was hearing.
Depends on what you mean by switched, I guess? Bowmage was weird but identifiably 2.0 bard with some extra junk layered on top. It was still buffs, dots, burst windows, yada, just a lot jankier. Bard 4.0 looks like they rolled back the 3.0 changes and followed it down an alternate path; it's pretty different from 2.0 bard, but you can still see the origins.
MCH in 4.0's play style has essentially no relationship to the 3.0 area aside from, for some reason, maintaining Wildfire's unique penalty potential (any other buff if a boss jumps early, you lose the last few seconds of the buff. with wildfire if it invulns early you lose the entire Wildfire.) 3.x MCH was a job with a lot of buttons that heavily focused on aligning a bunch of buffs in very specific burst windows every minute and a half, and was fairly active but not super cumbersome to upkeep. 4.0 MCH has far, far fewer buttons, no actual buff cool downs, fewer damage-dealing oGCDs and is more about a constant short cycle of build heat->overheat->build heat->overheat; at one point the guess was the target is to cycle that twice a minute if possible, and overlay Wildfire on top of one of those two, but it's a much more sustained damage process.
That said, MCH did get the HW bard treatment in that it feels a lot like the changes to the job are more a reaction to what they decided to do to Bard--Bowmage was probably a reaction to Gauss Barrel, and Overheat seems like a reaction to dropping Bard cast times.