What would happen if we introduced backtracking rules to CTF?

No backtracking worked in TFC because offensive classes such as scout were next to useless at dm'ing. Even if you watch frag montages, the scouts and medics are featured getting a few kills but mostly doing flag runs by conc-jumping and dodging there way through enemy fire to get the flag out of the enemy base. If you're a scout in TFC thats trying to strafe jump/conc-jump w/e your way across the map, there is virtually no benefit in stopping to kill an opposing class. You had/have one job, move the flag.

That is not the case in TF2.