Dealer recommends water pump replacement as its leaking, been leaking for 10K miles although must be very slow as not seeing noticeable drop in coolant from overflow tank. What else should I replace while in there ?

 

Maybe change friction wheel, tensioner, water pipes and drive belt.

 

+1 check the thermostat housing and expansion tank on the bottom for cracks. If you see the replace it. On the thermostat, if it leaks you will see a small blueish liquid right on the top of the transmission housing, if no leaks. Then you are ok.
Check the drive belt also while you are there and of course might as well flush the coolant if its never been done.

 

Jings, if it aint broke don't mess with it. Me, I would do the water pump and ancillary drive belt. The other parts recommended above if you have the cash. If the thermostat housing and rear water pipe are not leaking I don't see the need. Flush and refill with new coolant. The friction wheel maybe at 100K miles, Tensioner on a Gen 2 should be good for life of car unless someone damages it.