Once you've satisfied the RA vertical command, and you've either spotted the intruder visually or ascertained it's azimuth trend on the display, I don't see anything wrong with an avoidance turn.
For one thing, it will likely clear the conflict sooner so that you can resume your assigned altitude and track more quickly. In the unlikely event your manouver creates a new RA-generating conflict, the TCAS can provide resolution for multiple targets, and you'll have to comply with the second RA.
See and avoid remains basic. While the RA must be complied with first, and cannot be ignored, it is not the only tool you have.