What people seem to forget is that FDEV have to cater to all the customers who bought the game. Some of those customers like to be traders, like play at a moderate pace, and get annoyed when they are being killed deliberately and repeatedly by others, without any real reason. Some other customers like to play the anarchy type, they like to kill other players just for the fun of it and not get locked out of the game by doing so.
So FDEV are between a rock and a hard place. They have to find some middle ground to allow both types of gameplay but prevent one side from feeling on the short end of the stick. This is what these changes are meant to achieve - they are not designed to eliminate anarchic killing altogether (otherwise we could have just had automatic billion rebuy costs for any player kill - or simply invincible players to one another). The legacy fine mechanic is simply there to prevent repeated sociopath attacks in a certain area. This way there is some retribution for the actions of the attacker (because he has to move or pay the fine), and some relief for the victim (knowing that his attacker has to move).
I believe FDEV will achieve this objective, because I have seen both type of complains on the forum in the past days. I've seen people complain that this will kill PvP, and I've seen people complain that the penalties are not high enough. In my opinion, FDEV are on the right track.
As for the friendly fire and speed limit mechanics: just be a better pilot. I am having the impression that everyone who complains about this is not confident in his skills as a pilot. I too have accidentally shot security ships and rammed into other haulers, and you know what? It was entirely my fault. If I would have paid more attention to my windshield and to my sensors I could have prevented any of those events.
I think this is an important point. Elite and Frontier were not online games, and the developer (DB) could control a huge amount of what went on in the game. Unfortunately, nobody can account for human behavior.
I'm not convinced that what has been proposed will solve the problems, I'm pretty sure that the tiny minority will find a way around them, and in any case, as others have said, they're not actually playing the game, not trying to progress, not trying to increase reputation, probably not trying to find a system to call home. Unfortunately, those players who are investing themselves into the game, going for immersion will likely find their occasional transgression to be much more costly in terms of how it affects their gameplay.
I have posted often in FF threads, and I generally also feel that many of the FF complaints come from players thinking they are playing an arcade style shoot 'em up. Personally I believe that FF is generally avoidable, and gets easier to avoid the better I get at piloting and fighting. That said, I still get the occasional FF accident, and as you say, it's probably my fault, but I don't believe a seven day persistent bounty is warranted for that error. It was a 200 credit bounty, and the offense was not murder, or even attempted murder. So, FD will increase the threshold for FF, meaning that in order to get it right, and not be flooded with screams of outrage, they will have to make it very difficult to cross that threshold. The possibility of FF makes bounty hunting more fun, means that I have to think, and be aware of what's going on around me, and to take that away reduces the amount of skill I need to play the game, actually makes it more like an arcade game. That would be a shame.
Anyway, we'll have to wait and see how things pan out in Beta testing. FD are trying to solve what is probably an unsolvable problem. I wish them luck, because I've waited a long time for this game.