I'm really, really not spoiling for a disagreement on this one WHBM - I just feel that it's not quite as significant an event as the OP: I've stopped unscheduled many times for fuel on various aircraft/route combos - To me it just kind of goes with the territory. I can quite accept that there is another point of view however.
In my opinion, it very much depends on the inconvenience it causes.
On business, if I book a non stop flight, then I expect it to go non stop and I plan around that, accepting that one may encounter delays occasionally.
If I missed an onward connection due to a non stop flight becoming a stopping flight, then I would become at least irritated.
One of the reasons I like to use British Airways for long haul is that the company does have a fleet of aircraft that are fit for purpose, all year round.