If I'm on an offclass for more than 30 seconds, rando or yomps get bored and feed : (

I offclass on demoman just for a quick peek when I get a forward spawn, I generally switch off before I lose the forward spawn.

I would actually be in favor of the Roamer offclassing on *most* maps for last pushes because:

The roamer often contributes very little, beyond spam, to a last push unless they're baiting their team and doing nothing for a long period of time, unless manna falls from heaven and they actually managed to pick a door that was left open/doesn't get attacked. Especially now that most teams don't utilize double solly ubers as often.

Meanwhile, if you've got one of your scouts stuck on sniper your ability to "play the point" is limited because you likely only have 1 x2 capper on the team so you're far less likely to risk putting a scout on the point early and force the opposing team to fight you at the point (it's rare enough that a demo goes paintrain now, and even more rare that the demo would be the one to try to bait the point). Meanwhile a roamer stuck on sniper contributes about as much as they would otherwise - especially if they get a kill during the confusion.

I can see the argument that losing the splash damage makes holding intermediary lobby areas harder - but that would be something you'd want to test out in advance to see if it is possible to maintain a lobby hold down a solly some teams are far more passive on last holds than others - thus it wouldn't be as bad - Gullywash would be one of the more challenging ones for example because of the distance from riverside's sniper positions to lobby sniper positions would force some explosive class to have to solo hold lobby.