Playing with house rules (Praetorian/Urban cohorts at homelands, limited Heavy Cavalry etc) has worked for me, though. Too bad I can't resist the temptation to upgrade my units, so I kinda see why you're planning on this.

I myself am considering starting a campaign where Marian reform has been removed, so that I can finally really get a fair mileage out of pre-Marian Roman armies. Thus far I've never really had the chance to use Triarii for example...

I guess I'll fiddle around with unit speeds while I'm at it.