Star Trek TNG was it's own thing, but we got a cameo from a TOS character right off the bat. More followed a few years on.
If there's a logical reason for an OT character to appear, I'm all for it. It's just natural to wonder how our old friends ended up after all these years. I can even survive Anakin's ghost showing up, if it's important to the plot.
We probably could all agree on which character we don't want to see return though? ;)