Just get rid of the major choices bar. Make a major choice add/subtract Dik/Chick points at a much higher number. The way the Major choices bar currently works is that it makes it so people can never change no matter what past a certain point.
DPC won't change the gameplay at this point, so everyone will need to wrap their heads around it. DPC likes to herd players into discrete paths apparently.
Don't see the problem with the affinity mechanic personally.
If your major decisions involve fighting, drugs, prostitution etc. the 'nice' people think you're an ass and don't want to associate with the MC (some CHICK options become unavailable).
If your major decisions avoid partying and laddish behaviour, the 'party' people think you're boring and don't want to hang with the MC (some DIK options become unavailable).
Changing the mechanic to only CHICK/DIK points wouldn't change the results anyway (mostly DIK choices leading to being locked out of CHICK events and vice versa).