Mine didn't, even before I put the bar-sto barrel in it. Neither did my kimber 1911. My gun-smith recently bought a g22 because he likes mine so much and his slide doesn't wiggle, as far as I can remember.
My Gen3 G27 (2years old) and Gen3 G23 (bought used 2 years ago) both do, they've had atleast a couple thousand rounds through them. But my Gen4 G17 doesn't but i bought it last years and i don't think its got a thousand rounds through it yet.
It is. The polymer frame has less contact points with the slide and the rails a built to a greater tolerance. It's part of what makes it so reliable.
It's normal. The most recent production Glocks have pretty loose tolerances. My NRR-prefix G27 has some play in the slide while the slide is in battery, there's no magazine in the gun, and the trigger is rearward. My GEA-prefix G23 has absolutely no play.
