I don't mean to suggest you're wrong here, just commenting for the sake of discussion...
Do you think that's a valid concern?
I guess there
might be situations where you're out in the middle of nowhere, getting into bother, but in the course of "normal" PvP, I tend to think that if my canopy goes, it's time to call it a day and head for the nearest station.
You're not going to make use of an AFMU while you're
in combat so you're going to have to bug out.
And if you're going to bug out, you might as well bug all the way out, back to the nearest station and make
all necessary repairs.
Which shouldn't be a problem, even with the usual D-rated Life-support.
Also, I can't help thinking that if you're getting your canopy shot out so often that repairing it becomes a predictable necessity - and your ship is otherwise undamaged enough to go straight back into a fight - you probably need to look at a different ship, a different build or using different tactics.
I was flying a Viper 4 for a while and it seemed like a common tactic was to go for the canopy of that.
When MRPs and HRPs became available, it seemed to reduce that weakness and it stopped being an issue.
Either that or I just started getting better at evading incoming fire at roughly the same time.
In either case, I never really found that my canopy was fragile enough to warrant considering repairing it in-flight rather than just fleeing to the nearest station.