Some of the radio handling bits on MSP430 would be more complex due to the lack of 32 bit support. There's also some third party firmware for e.g. the lowpwan stuff that's only available as Cortex binaries.

TI keeps trying to push their MSP432 cortex-M4 series on me as a replacement for MSP430. I guess they don't want to have customers go with a different vendor just because TI doesn't have an ARM solution that supports whatever code module or toolchain the customer wants to use.