My 2 cents worth:
In the early days of aviation, there was one spot where all traffic converged. That spot was the aiming point on the runway.
So we created the circuit with a direct downwind join. All of a sudden we now have a different spot where all traffic converges. Roughly mid-downwind.
So we created a new procedure so that you can see the circuit traffic before joining it, by flying overhead. Now all traffic converges overhead.
And when the Mk 1 eyeball didn't work due to speed or cloud, and we started flying on instruments, we moved that spot somewhere else and called it the IAF.
So let's face it. Whatever procedure you follow, there will always be a spot somewhere in space where the traffic converges.
Personally I prefer the direct downwind join under a 90 degree angle like what's prescribed in the Netherlands, or under a 45 degree angle like what's done in the US. The advantage is that at that point in space traffic is at the same altitude (at least in theory), that there's only a few places where traffic can come from and there's only one direction it'll be flying to.
With the OHJ, traffic can come from 360 degrees around you and might at that spot actually be turning head-on towards you. Plus, the CAA OHJ requires two distinct altitudes (circuit plus OHJ altitude) each offering sufficient clearance from terrain and from each other.