Not much to add really to the bug I’ve filed here: bug#67099.
I personally can think of some very nasty consequences of applying this on the slaves I manage, and the reason I’m posting the bug is that while I guess this is too late to fix in 5.6 as it’s effectively a new feature, I’m sure many sites may bump into this and be somewhat disappointed if they want to use the new GTID feature and have several slaves. Hence, if the fix/feature has to go into MySQL 5.7 then I hope it goes in sooner rather than later. We will see.
I probably should have updated this earlier but it does seem that Oracle have taken these comments on board. See: WL6559. It looks like they plan to do this for 5.7 which is good news. I’m really hoping that we will not have to wait too long for this version as it has other “goodies” which are going to be interesting. Reducing the time of the release cycle will I think allow those of us who appreciate these new features to have access to them sooner.