First of all, the NPCs used to be exactly like that. They got dumbed-down because people didn't think they should have a responsibility to defend themselves if they were 'just exploring' or 'just trading'. NPCs out in the middle of nowhere, no, that shouldn't happen. NPCs attacking you in the bubble on your way home? Yes, absolutely should happen. And I say that as an explorer. There's no threat from NPCs anymore, and the only danger I ever face as an explorer is from players. That's why I stick to open. Because no risk is boring. And no, there's no risk from 'unexpected gravity' and 'high heat' that aren't easy to mitigate, so don't go there.
Secondly, and on that note, prepping to face the 'dangers' of deep space is easy. Because there is no danger. I'm 20k ly away from the bubble in a Sidewinder right now. If you know what you're doing, it's impossible to overheat, impossible to run out of fuel, impossible to crash on high-g worlds, impossible to get surprised by high gravity (because it tells you straight up in the system map what gravity a planet has, duh), and there is no threat to me. None. The only prep I needed for all of that stuff is a coupla heat sinks and a fuel scoop. With heat sink synthesis, a good stock of mats, and conservative usage, heat is no issue. With a fuel scoop, and fuel-stars marked on my route filter, I'll never run out of fuel. As for high-g worlds - please, nothing that G5 dirty drive with drag drives on enhanced performance engines can't handle. Speaking of which, that's my defence, and the only one I need. Almost 800m/s, and most ships fit for PVP can't even get pointed at me to fire a shot before I'm already high-waking. Oh don't get me wrong, if they did get a shot, I'd be plastered all over space with little more than a sneeze, and with 20k of data, that's no small loss.
Do you know what, though? It wouldn't bother me. Because it's just a sidewinder, and it's not like I can't go exploring for more data to sell. I don't explore for the money. I explore for the novelty of it alone. The experience. Money in this game is easy, but if it's money I want, I don't go exploring.
As for distant ganks "making no sense" and "being mean spirited", you're attributing intention without actually knowing anything about anyone doing it. Just because you can't make sense of it, doesn't mean it doesn't make sense. I think it makes a lot of sense. I've had more than a few explorers already ask me for advice on how to avoid losing ships to such gameplay, because a threat has been identified, and rather than give up and abandon open, they want to keep on keeping on, with the ability to mitigate the risk they'll be taking on as they go. They have the right attitude, by virtue of not asking to have their hands held by the developers and are, instead, applying the tools already available to them in the game to make their experience more survivable. As for "being mean spirited"... well, der. Ever game needs its villains. In Elite, the only villains with any real threat value are players, because the NPCs are all generic cookie-cutter carbon-copies of each other with no spirit at all, mean or otherwise.