The reason for the crappy black levels of today's IPS panels isn't the 1000:1 contrast. IPS has an issue called white glow. Older NEC IPS panels used the A-TW polarizer to greatly improve their black levels by getting rid of this white glow. If PLS uses a similar approach to the A-TW polarizer black levels could be perfect. If it doesn't they won't.
Contrast ratio doesn't take viewing angle effects like the white glow into account at all. It estimates how black your black is at the best viewing position possible - right in front of the display at the center of the screen. And I cannot speak for everyone, but in my opinion my U2711 has great blacks in the center of the screen with its 1000:1 contrast ratio. The only issue is the white glow, it would ruin the blacks even on a display with 3000:1 contrast. You can hope that Samsung has something to fix this issue, but there's no guarantee and no number will be able to tell you the answer, you have to see it with your human eye.
I don't think Samsung will use an polarizer, they already have good blacks with their PVA technology and from what i heard PLS will be a combination of IPS and PVA, taking both of their advantages. I hope the black crush won't be there as for PVA...