If you feel somewhat bad about demanding a new pair of skis, look at it this way, you purchased "new" goods. You did not purchase flawed or damaged goods. The shop, when they improperly mounted the skis, damaged your skis. Your purchase was not on flawed, damaged, or second products, it was a purchase of new, unused, non-flawed goods.
In terms of resale, yes they somewhat (keyword somewhat) are trying to screw you, a ski can and will 99% of the time only be drilled 3 times by a shop. Therefore, if they are already on their second drilling when they see snow for the first time, then the bindings can only be moved (requiring a drilling, not a simple close bit sole move) one more time (which can mean if you choose to change binding companies next year, that require a different pattern, the skis will not be able to be drilled beyond that).
Hopefully this makes sense as it seems I confused myself a little even though I know what I'm saying.
Basically, do not feel bad about demanding a new ski. Furthermore, do not stress about a lawyer, should not be needed at all. The shops reputation should be enough fear. People have to realize how much power they have, how much business they can either bring a shop or deny a shop.