The 5/7 foot hose will come up around the back of the neck and be able to hang on the chest. This needs to be un-wrapped in removing the gear.
Removing the long hose from a diver when removing the gear is really simple, it's not wrapped around the neck, it passes behind the head. Any hose can get tangled up a little. BP/Ws tend to be very simple streamlined rigs with a minimum of clutter, and as such are pretty easy to remove. And anyhow, gear removal is a low priority for rescue, typically occurring after the injured diver is either on shore, on a boat, or immediately prior.
Getting back to the overall issue of safety with the long hose, if anything there's an increased safety element due to the MUCH better air sharing convenience and immediate access to the alternate. There's a reason that the vast majority of technical divers use the long hose/bungeed alternate, it's just a much better system for air sharing. This means increased safety.
As far as the "training" required to use a long hose, I think that's nonsense. As I mentioned before, a real OOA scenario often results in the 2nd stage being forcibly removed from a divers mouth. I got a kick out of someone posting on this thread that they were "trained" to offer their alternate and hang onto their primary to prevent an OOA diver from taking it. Not sure what planet that instructor is on, but here on earth I can assert from experience that a truly OOA diver is going to get that 2nd stage FAST. Trying to fight it is pointless, and anyhow it's probably in the OOA diver's mouth before the 'donating' diver even realizes what's going on. It's a really good thing these sorts of scenarios are rare; the only reason the big recreational agencies can get away with teaching the nice polite fantasy land OOA scenario is because most of their students will never encounter the reality of a drowning diver mugging them for air.
What is common, though, is a diver's 2nd stage becoming dislodged accidentally and/or momentarily lost. This is where the bungeed alternate really shines. It's right there a few inches away from the diver's mouth, even accessible hands free with a bit of practice.
When one looks at all the factors, it's very difficult to successfully argue against the logic of the long hose/bungeed alternate.