Ok, frankly here’s the problem:
Anyone on the Canonical payroll who is capable of enabling this, won’t do it, because they have an ever-growing list of other things to do. Getting update control on their to-do list requires going through the Guardians of the Galaxy, and prioritising it above whatever else they’re doing. That means architect / design work.
Anyone who isn’t on the Canonical payroll isn’t motivated to do it, because chances are (see above) whatever implementation they come up with may be rejected, or left in pull request limbo.
I started this thread over a year ago, in the hope someone on the snapd team might pick up on the various hints from the community that forced updates with no off-switch was a frequent, frustrating, pain point. Sadly the issues is blocked. I failed internally to get any movement on this. Unless someone has very strong technical and negotiation skills, this won’t happen any time soon. Sorry.