This whole things makes me rather sad and angry to be honest, I've spent far too long arguing about it in the past.
What it comes down to is people have lives outside of the game and it can be difficult to predict when and for how long you will be able to play. If real life intervenes it is a tad unfair that you are then punished in game.
I don't object to missions being timed, not at all, but I think that should in game time not real-time. There would be a few interesting mission terminating edge cases but nothing that wouldn't be rather rare and nothing that couldn't be resolved sensibly.
Frontier's response to this has been to extend mission timers out but that just reduces the validity of those timers for everyone who can spend time in game while not helping everyone else that much.
So, bit of a mess and generally annoying.
There was some _very_ long ago talk about timers being in game but that never amounted to anything - I suspect it is sufficiently built in to the fabric of the game that changing it would be a right pain now.
In relation to CGs I think the real-time is probably okay, these tend to be long running events and I've always maintained that for player interactive events (which CGs sort of ought to be) or missions then real-time makes sense. Just not for everything else.
Still, I don't expect change at this point. I just have to be super careful about what missions I take when - that this care is based on factors external to the game rather than internal is immersion break and irritating but oh well.