I dunno, I can't help but feel that there was the potential to do a lot more with Shadowrun-as-an-FPS. At the very least, they could have randomly generated the maps and given the defenders time to modify said map and install some defenses in clever places while the attackers collaborate on a plan of attack based on their increasingly-outdated plueprint. That alone would have helped captured the feel of the tabletop games better than just CounterStrike with Mages and Cyberware.
An MMO backend might make it even cooler, but only if you had a player base who actually cared more about re-creating the feel of the cyberpunk setting than about raising their stats and accruing wealth and power. Eventually you reach a point where the more intuitive the game is, the more jerks play it, the harder it becomes to maintain authenticity... hmmmm... UNLESS... What if it were a sort of Co-Op Massively Signle-player... Each player is the only PC in their area, and they could use a communication tool to get in touch with other players... I guess kinda like COH... meh, now I'm just rambling.
The point is, I think Shadowrun could work great as an FPS or an FPS hybrid, but the PC FPS didn't give the players enough of a chance to come up with a plan, and then ruin the other side's plan. That's the essence of Shadowrun, right? Pitting elaborate player schemes against Murphy's Law?