I could have sworn I already said above that you don't have to edit the startup file...
I just wrote a simple msp432 program for testing last night that used the timer interrupt for a programmable delay. The result looks almost identical to the MSP430. The register setup looks basically the same, the ISR looks only slightly different, and it has an extra NVIC call, that's about it. No editing of the startup file, no "#pragma vector" syntax in either one.
Maybe you had to edit the startup file previously, but it was still pre-release silicon with pre-release software support. If you don't want to deal with pre-release "problems" then wait until the device has moved to active production.