The only difference that platform screens/doors would make to the operation of diesel trains is to completely prevent them from running (again, the doors wouldn't line up)!
This raises the question of why don't we have any electro-diesels, these would use exteral electricity where available and genetare their own away from the wires, if you want the same trains to run over both non-electrified surface track and and underground, electro-diesels are the only way to go. But we could electricfy our country services, in which case re-electrification of the suburban railway network would also be worth considering.
When our underground stations get their makeover, platform screen doors should be included in the upgrade, the need for them is beyond debate. PSDs do work, regardless of how trains and controlled, can be compadible with all door arragements and with all (permissible) stopping postitions
The only pre-requisite, as far as I can see, is for doors on both the platform and the rolling stock to be fully power operated, which seems to be standard on all new trains, trams and buses available today. It's even ironic that the Hitachi and Comeng sets have hand operated doors when all our buses and trams in service at the time, even the W class, already had power operated doors. Our Xtrapolis and Nexas sets have push button operated doors, so the PSDs should also be button operated.