A bit of pitting is not necessarily a wheel killer, you might get away with
replacing the balls and a generous lubing, especially if you ride off road
mostly. There will be increased friction but doubt you would notice much.
If you want to replace, this would be a good opportunity to do a minor
upgrade to cassettes and a freehub wheel. 7spd cassettes are not much
more than freewheels and you could easily upgrade to 8-9spd by a
fairly inexpensive shifter change. The deraillers would work as is. The rim
could be recycled to a new wheel, maybe even the spokes though most
posters here would recommend new spokes. If you are a fly weight and
doing non technical riding and the spokes haven't been damaged by
chain derailing into them then you could probably get by. Spokes are best
changed however, and a good eyeball on the rim for brake surface thinning.