Different CoF for "pros" and "amateurs" could be a logistical nightmare as the stages are run at a pace to get everyone through and minimise standing around. If the stage time limit was the only difference on it could work, but a but of a headache for the RO.
The small and big gong idea has been tried (shooter had to nominate size before starting, and stick with it: double points for the small gong.) However, doubling the number of targets increases cost, set up time and complexity. Possible, though.
Factory class goes some way toward reducing the arms-race effect of open class. Similarly "limited" (223/308) class. I think Hunter class would be a good idea; I used to use my 308Win Stalking rifle for PRS type shooting and had great fun despite needing to do a mag change on every stage.
As someone said above, Tom Rice won (I think) with a factory Tikka not that long ago, so I'd encourage anyone interested in PRS to try it with what they've got, before building a dedicated rifle.
Kit like bags/tripods etc is freely lent on the firing point, so again, don't buy stuff before you've tried it.
I'd certainly welcome cheaper matches and more venues.