Dear Reef,
I guess that the beckett skimmer you have currently is from Ocean Werx.
From the pictures that you've posted, my suggestion is that you still need to tune down the air intake. The bubbles created are way too large for my liking as well.
Secondly, raise the water level in the skimmer. As we can all see, the skimmer is creating reasonable foaming (obviously yellowish / brownish foam awaiting to be expelled out from the neck), but the water level is set too low. You will only get dirty and muddy neck, which on the other hand is also skimmate (just much thicker, smellier and more messy)
I agree that with a quick release, the collection cup can be removed easily. However, you are not required to undo all the thumbscrews to remove the collection cup. The recommendation is usually to loosen the thumbscrews and twist the collection cup. The keyhole flanges are specially designed to allow this function.
As for the air vent that you've suggested, it is not really necessary. The drainage size is specifically chosen to provide sufficient allowance for the air to escape without compromising on the skimmer's performance.
The whole reaction chamber of the beckett skimmer is fully utilised for extended reaction time. We had been contemplating on whether to re-design the beckett skimmer to prevent micro-bubbles from escaping. But upon weighing the pros and cons, we rather advise Ocean Werx beckett skimmer users to prepare more buffers in the sump to minimise the micro-bubbles.
Really appreciate your time to do up this review and finally post some pictures as well. From the way I look at it, a porche still needs a good driver (whether or not they are ugly).
PS: never knew that a BK is so cheap in NZ, or is deltec really that expensive there. In Singapore, the cheapest BK is standing at the top at around SGD$3,000 while a Deltec AP702 is only SGD$2150 or lesser. http://www.eaquanature.com
Not too sure if my comparision is appropriate though.