You just described doing the flaring maneuver during an uncontrolled buoyant ascent.
Why do you assume this type of ascent is uncontrolled? I described exactly how to control it.
What is your definition of "uncontrolled"? We never got an objective definition of "overly thick" yet either?
Have either of you two ever dropped a "heavy" weightbelt while wearing a "thick" (5-7mm) wetsuit at depth?
If not, I will give you a little clue as to what will probably happen: NOTHING.
With zero air in the BC and the thick wetsuit that is nearly completely compressed, the diver will be close to neutral, if not negative while wearing the tank.
I remember one time I left a 12-14 lb weightbelt on a ledge at around 80 feet in a Florida spring while wearing a 7 mm full suit. I dumped all the air from my BC and just swam around with zero air in the BC - it was a nice feeling without the heavy belt and the BC puffed up.
Unfortunately a couple of dick's found the belt and took it to the surface. I came back 5 minutes later and found the conspicuously placed belt missing and then ascended. I did use the cavern walls a little for the last part of the ascent, but not a huge deal. I asked the GF if any divers had recently surfaced and she pointed to "those two guys" loading the car. I rushed over to them and demanded they empty the trunk and at the bottom of their gear was my weightbelt.
The point here is that in a true emergency, when all other good (better) options have been exhausted there are some viable actions a diver can take to make it to the surface after dropping a belt. The diver will most likely be negative or neutral until a depth of maybe 30-40 feet. They can conceivable stop and rest there, do a deep safety stop. Once they have caught their breath and rested from the swimming ascent, they should be able to maintain a reduced lung volume for the 30-40 second period it might take to ascend the final 30-40 feet under buoyant conditions. For a recreational diver, who is calm and and can keep the lung volume reduced (but still breathing) it should not be that big of a deal.