We don't do OH 4x4, or anything like that. Honestly the biggest reason that I see for why feet should certainly remain an event is for comic relief, and the people who are grossed out by it need to get over themselves.
In general I'm in favor of making it easier for individuals to compete (i.e. easier cutoff times)
I don't see how adding 4Feet would be so much harder than adding something like kilo.
We already have scrambling programs for it, and people know how to scramble a 4x4.
In the case of kilo, they had to create a new scrambling program. I don't think it was that hard, but they still had to do it.
I'm for Ao5 3Feet and then bringing in 4Feet.