let us be honest - great park itself is a burden alone regardless of 108 acres from the City. Even today its a PITA on the 5 and 405, just ask anyone that lives in south county and has to commute up.
To specifically address the issues in that part of OC, short of:
- doubling size of the 73 and forcing people to use it (but either free, or greatly reduced fees to something of a symbolic cost)
- strongly considering double-deckers on the 405/5
- lots of new off ramps to better distribute incoming traffic
I don't see how its going to be good even with just GP addition.
Any of the options will be strongly expensive because of all the homes built (buying out so many nearby homes ain't cheap - ask Disney with Starwarsland), and the opposition from people to see any nearby freeway near them expanded. It would take an act of political will that drove the 10 fwy into existance.
