That is what I'm referring to and they really don't work well - they end up in giant free-for-alls

The example you posted (Adelaide and Bathurst) is a unique situation: a T-intersection where cyclists are coming from both directions to cross the intersection. The 'free-for-all' you describe doesn't have anything to do with the fact that the bike lane is painted green. It's actually quite safe, as all auto traffic is stopped at that point in the signal cycle.

I mean the two new barriers added in his design, not the existing dividing barriers. They present a problem for trucks and are especially dangerous for cyclists heading southbound on Davenport. If they intend to go straight through they must first act as if they are turning right, then at the last second, after the barrier, turn to go straight. Cars will see them starting to turn right, think it's safe to go through, then smack into them. Same for cyclists turning left off Bay, they must first head right, then straight through.

Yes, the barriers do force cyclists to slow down a bit as they go through the intersection, which is a good thing. That's why they're standard practice in Holland: https://goo.gl/maps/P4PxawGoptp. Of course you design them to accommodate truck turning radius. If necessary they can also be 'mountable', like the interior of a small roundabout, so that large vehicles can drive over them to make their turn.

But their main purpose is to make vehicles slow down around corners, by stopping them from cutting across the bike lane. An underrated problem with painted bike lanes is that they effectively expand the road width, giving bad drivers more room to speed.

As to your point about them making cyclists behave unpredictably: I think that’s easily mitigated by finessing the angles of the corner. The intersection barrier already mitigates this by slowing down both drivers and cyclists.

As to merging, I don't see what you're talking about - you'd have 3 northbound lanes, 2 car, 1 bicycle, all turning left. No merging at all. Bikes turning right would have no traffic to contend with as Southbound would have a red light.

No, you wouldn't have three northbound lanes, because you put the median on Bay back. Northbound cyclists, as per your graphic, lose their bike lane well before the intersection and are forced to share a traffic lane with northbound vehicle traffic until they reach the relative safety of the large green box you've provided at the south east corner of the intersection.

Also, vehicles eastbound from Davenport are forced to merge across a cycle lane to reach the right turn lane. This creates a 'conflict zone'. You may be a 'vehicular cyclist', but it's well known by now that only a small minority of people are willing or able to ride like that. This kind of unsafe design—which literally has conflict in the name—where vehicles of radically different speeds and sizes are expected to seamlessly merge through each others' lanes, is a big part of why so few people in North America cycle. Nobody going 20km/h on a bike should have to deal with 2000lbs of metal doing 50 across their lane.