only eternal mana has value sealed.
And all 3 used go for $15 each at ebgames
So from a used standpoint, there was little value here to begin with.
From a new/collector standpoint, you'd really want to have the soundtrack for the 1st game, which isn't being reprinted, and so the value should be fine.
If you have a sealed SMT: Nocturne (with soundtrack), the value really didn't take a knock when the game got reprinted.
Still, if you are coming from the conversation as an investor/collector, you CAN'T be surprised when this happens. There is always a chance for reprints, or reissues. Just like investing anything, there is risk.
In this case, you can minimize risk by either buying sealed copies at very low clearance prices, or to buy when they have limited items that are very unlikely to be reprinted.