Overall, I think it's a good idea, but you have to get the everyone onboard with it. I've seen guys block lanes, open their car doors, you name it to prevent guys from splitting lanes.
I bet that making it LEGAL will do a lot towards reducing that kind of antagonistic activity. My brother in San Diego who rides says that drivers in CA have now become so conditioned to lane splitting, that they expect and anticipate motorcycles to be BETWEEN lanes, to the extent that if he decides to ride WITHIN a lane, he needs to be super vigilant and protective of the space.
Filtering, (or splitting in the CA model for that matter), involves LOW relative speeds. At 15 mph, I have no problem stopping or swerving to avoid a car door, or more importantly, a pedestrian crossing mid block between the stopped queue of cars, or a stray dog. At the slow relative speeds, I've never been doored. Who wants to open their door and find they can't close it again because a motorcycles front tire is in the space, and there is a pissed off looking, 6 foot guy in a black leather jacket standing right next to them? Also, by waiting until traffic is essentially stopped before revealing my movement to filter, individual vehicles are left with no ability to maneuver into a blocking position even if they decide they want to. They can't move sideways.
Big bike guys on their "real" motorcycles may be stuck in the queue, but on the small, highly maneuverable machines I prefer for urban commuting, like my 150cc scooter, or 250cc Suzuki, it's no problem to pass "that one guy" who has decided he needs to block on the parked car side, by circling around on his left side. Here in the city, one already has to be cognizant of an assortment of different modes of travel. That space is already populated with bicycles, electric stand-up scooters, and more, all of which have legal right to the road. Even bicyclists can't legally ride on the sidewalk. The 4 wheeled folks HAVE to share, no matter how entitled they feel, or ignorant of the rules of the road they are.
What I'd like to see here in Chicago, is law enforcement enforcing the right of way of bicyclists. The city built 420 miles of bike lanes, but I've never seen, nor heard of any car driver being cited for encroaching on these lanes, using them to pass on the right, parking in them, etc etc. Meanwhile, hundreds of cyclists have died, in so called "protected" bicycle lanes and bikeways. The city built the infrastructure, but did nothing to shift the mindset of car drivers away from the car centered culture of 50 years ago. I hate to say it, but it will probably take an expensive class action judgement to get any change to occur.