More questions:
5) Does it happen in all view modes (Window, Full Screen, Unity) or just in Unity mode?
6) Is the problem intermittent, or is it 100% reproducible?
7) Are the VMware Tools up-to-date inside the VM? If in doubt, un-install them completely and re-install them.
8) When you perceive the mouse lag, what do you see?
a) 2 mouse cursors (host and guest)
b) Only the host mouse cursor
c) Only the guest mouse cursor
9) If you replied #b or #c to question 8, how do you notice the lag then? Is the lag a speed problem or a displacement problem. I.e. when you move the mouse in your hand,
d) does the mouse cursor on screen eventually reach the destination that you expect, but you see it travel slowly,
e) or does the mouse cursor on screen travel at normal speed, but you see it reach a different destination than the one you think it should reach
?
10) Do you use a Retina display?