It won't work period, mainly due to the fact that pigmen do not pass on aggressiveness like they do on the java version. What I mean by that is that if you agro a group, and some die, then others spawn in, even tho some which are still agro on the player, the new ones which have spawned in are not agro. I tested this quite awhile back in creative. I could get the spawn rates fairly decent, but sadly argoo issued killed the concept of the farm.
I did not report the issue or even check to see if it was reported, due to the fact that I have little faith left that the bedrock edition will pan out to be anything other then a block builder.