Especially if the inherent anemic schedules and resultant subpar usability tank ridership to the point that the state kills Phase II outright, in which case FR/NB are left with mediocre service and the rest of the Old Colony is screwed too. I think a lot of us concerned about Phase I aren't so much opposed to the idea of it as to the danger that its inadequacies will cause SCR to fail outright, with collateral and completely avoidable consequences for other services as well.
This is my biggest concern. I would have fully supported a phased approach that had SCR running from South Station to Taunton via BBY and Stoughton with supplemental bus service between Taunton and Fall River/New Bedford as Phase I. It's been said, but Taunton is the city that benefits the most in a full build out as it's closest to Boston and will see more frequency than both Fall River and New Bedford. Taunton-Boston via Stoughton is viable standalone service that could easily be extended/built upon if demand is there (and I'm fairly certain it is). But I question the political will for going through with Phase II of the current plan if Phase I is as weak as it appears to be.