Well, on many AK's, if you pull the release with the AK held level or angled downwards, they'll drop free of their own accord. If you want them to move a little more freely, you could apply some oil to the rear locking nub or even file it some. As the gun breaks in, they should also drop more freely. A tactical mag change with an AK typically involves using the new mag to press the release lever and sweep the old magazine out in one smooth motion. This also places your hand in a good forward position to rock the new mag home.
I had a similar situation with my Saiga 12's mags. The Saiga 12 is an AK-based shotgun, and uses the same mag release design. The top rear corners of the polymer Surefire mags were catching on the magazine well, resulting in them not dropping free and sometimes requiring a bit of effort to extract. I filed the corners where it was catching, and now the mags drop free under gravity when the release is pressed.
