If you have a dealer willing to make that swap you have to figure it's because he feels he can make a considerable profit, especially on two of those pins (LOTR and TAF).

They are both very desirable, and if yours are in really good shape will be highly sought after.

I have GB pro, love it, and think it's a great new pin, but I don't think I would ever trade my LOTR for it, it is just an undeniably classic fantastic machine. I might consider swapping my STTNG, because they're more of those around and easier to get at a lower price.

Have you considered just selling one of your three and then picking up a nice used SM, GB, or TWD, or even a NIB one of those versions if you feel you want to go that route, instead of swapping so many all at once? At least that way, you're keeping the profit from the sale rather than giving it to the dealer. ( assuming you bought those three pins several years ago and can sell them at current market prices?). I think it's a valid point that your wife is making about relative values.