What METRO needs to do is better coordinate the first / last mile problem. Along the LOSSAN corridor, OCTA is the only one that has the first / last mile issue solved. Also, cars need to stop being considered an enemy to public transit and used as a hybrid system as is done in Orange County. People use the free parking structures built by OCTA, to park their cars and take the train to work, or leisure destination on Amtrak. Some even park their cars on both ends of the line so their the first mile / last mile issue is not an issue. The OC line is the only line on the Metrolink network that that actually has an increasing rider base.
Another thing that also probably helps the the OC line is the availability of Amtrak's Pacific Surfliner rail to rail program for monthly pass holders. Having hourlyish train service between LAUS and Oceanside gives riders much better options for example when you leave work early or when work runs little late.