can't come down to Earth
It is only unfair if they don't earn the Olympic spot through process qualification.
Sure... as long as your federation puts you forward then why not? I think there is a lot of leftover feelings from when it WAS strictly amateur vs pro and the advantages of a pro coming back when the name of the game was "paying your dues". Back then it wasn't fair as skaters had played the game only to be told in an Olympic year that the game changed - sorry. More time and money with no gain in earnings because there had been no olympic exposure.
But now that all the earnings rules have been relaxed (Yu-Na Kim and her 8 million dollars! yikes), they are all pretty much on even ground. The "pro" has just taken a little break, and is older... that's all.
looking for fresh blood
As long as the spot is deserved, then why not? I bet other skaters would feel cheated to even win a medal at the Olympics while knowing that their toughest competition wasn't there because of a barring them from participation (a good example would be Davis/White admitting that this Nationals really felt like their first Gold since they beat Belbin/Agosto fair and square on the same ice at the same competition).
If they DID want to make some rule about it, the only one I could think of would be that the team would have to compete in at least one international competition before or after the Olympics in the same season (be it 4CCs, Euros or Worlds)... perhaps maybe have it so that they should compete in Worlds afterwards to secure placements for new skaters for the next season. The only thing I ever thought unfair is when skaters back out of Worlds after winning the OGM, sure it would create controversy if they don't match their win, but what if backing out means less spots for your team next year?
Sure. if they qualify. And if they have made a few bucks here and there, more power to them. Skating is expensive.
I don't see Pro's returning as an issue if they've earned their spots on the teams. As others have pointed out, amateur vs pro was about making money. Since the rules about financial earnings were lifted, the line has totally blurred. If the returning skaters are better than the younger, then they deserve to represent their countries as the best of that country. It's not as though the returnees don't have to train and sacrifice as much as the younger kids - if anything, training becomes harder.
As evidenced by the 1994 Olympics, being a returnee is not a guarantee for a medal either. Brian Boitano didn't even go as the US Champion - he got the second spot after Scott Davis won the US Championships that year and neither medalled at the Olympics.
Teams like Brasseur and Eisler 'lost' with the presence of returnees, but, then again, they didn't outskate the 2 Russian teams .
Shen and Zhao returned better than ever. Germany's S/S just happen to be having a rough year and I think that hesitancy was evident. While P/T had THE performance of their career during Oly LP, I don't think P/T nor Z/Z had developed that totall connection where 2 skate as 1.