S/N ratio and readability of t he actual signal seems lower than the MLA30+
Many things seem to be lots of things; beauty is in the eyes of the beholder. Your statements are very contradictory though. Anyway...
Behold then that in your video the apparent S/N ratio of many signals
increases significantly when the Wellbrook is switched to. But, this is all entirely a subjective analysis because signals aren't steady and the two antennas aren't occupying precisely the same space with the same orientation and directivity. Do you have the 3D antenna pattern analyses of both antennas at their exact mounting locations so that the slightest amount of scientific method can begin to be applied here? Otherwise comparing signals is all Kentucky windage.
The performance of the transimpedance amplifier component of each antenna is properly measured in the lab, where it's isolated from all those signals displayed in your video. Similarly, the performance of the antenna assembly is measured in a RF-tight anechoic chamber, where it's isolated from all those signals displayed in your video.
Otherwise, you've way too many variables involved and any analysis is subjective, i.e. NON-scientific.
If you want to try a slightly less-non-scientific test,
disable the AGC on your receiver, couple a signal generator to each antenna, set its level to a few dB under your receiver's saturation point, using the same signal level displayed by your receiver for each antenna though, and then switch off the signal generator and measure the noise floor. Repeat for several receiver bandwidths to maybe get some idea of how much receiver performance affects your measurements. Also, if your receiver is supported by Linrad, and if so after calibrating the combo, and disabling your receiver's AGC, you may be able to make better subjective measurements. What you're using for a receiver matters a lot if you're actually trying to measure something.
Another similar test you can try is to replace the loops with inductors having the same value as the loop element, and then measure noise floor and S/N ratio as above. Differences between inductor and loop can reflect reciprocal mixing in the amplifier, oscillations, etc. Again, the proper place to do definitive analyses is in the "RF lab" and not in the field where influencing variables can't be eliminated.