Boots wiggle a little in new bindings

Its probably because your bindings are set up a little bit too big for your boot but still small enough for them to fit in so that its loose

you got marker bindings instead of another company that's why it wiggles. but in all seriousness move your forward pressure in a bit on the heel piece to snug up the fit. my sth2's they need re adjusted every 10 days of riding or so depending on how much choppy snow I was riding. definitely get that adjusted pre release is no fun on skis, you usually eat shit pretty hard.

^ 100%

old boots get work down in the heel and toe, could be the problem?

I get the same thing on my griffons. Once you get your new heel pieces in take your skis and boots to a shop and get them all snug properly.

crank ur dins

Your forward pressure is propably off.
Here is how you can adjust it:http://theskimonster.com/blog/posts/how-to-adjust-your-marker-ski-bindings/

koolkalecrank ur dins

Definitely not this.

And it could be forward pressure, but if the shop you brought them to to set them up is at all competent, I doubt it. it would be extremely unlikely that the binding would test out correctly if forward pressure was off, and the shop is legally required to do a release check on any binding they mount. If it was because the heel piece is too worn, then, again, any shop worth anything would have known that and told you before mounting it. More likely it's toe height being slightly off. Still a basic thing a shop should check, but much more likely that slipped by them than something as basic as forward pressure or an overly worn heel piece.

marker bindings have a lil wiggle, especially noticeable riding the chair. It's most likely that, but it could be a forward pressure issue, or a matter of your boots being very worn down in the toe and heel from hiking or walking on rock/pavement. The marker "problem" isn't really a problem while skiing. My setup however...while on the ground, if I go to roll my ankles and my boot moves first, then my ski....that's problematic.

There is a adjustment on the new marker bindings that I have found shops will over look. The plate under the toe bail on your toe piece can be adjusted up and down. Clip your boot in make sure there isn't a gap if there is adjust it so a business card will slide in and out with a little resistance.