I think FCP is a very viable defensive option, however it requires a team that's more specifically equipped to run it that LI does.
FCP lowers your Defense, Rebounding, and Stamina in return for higher forced turnovers. I think if a team was structured such that they had higher levels of those three stats and ran an Outside oriented offense to compensate for the cost of bigs with exceptionally high rebounding that FCP could be a force to be reckoned with.
I have the same feeling about zones... it's not the zone that's broken, it's the type of players we pump into them. Zones require more SB.