OP - not sure what your problem with assassination missions are, but they work perfectly for me. Not had a bugged one yet. Suggest you raise a ticket with FD if you are having problems.
You gotta be kidding. Don't get me wrong, they aren't 'broken', but they are HELLA buggy.
1) You could be sent 1m light seconds and the payout will be no different, I know some say this is working as intended, which may be so, I still think it's supercrap.
2) The mission USS when you finally arrive could pop up in 2 seconds or 15 minutes. I can usually get it to pop within 5 mins these days, but it's stupid and annoying. Especially when the body is a star, it seems to be particularly difficult to find the sweet spot for the spawn.
3) About 1/3rd the time you are sent to 'Find a contact'.
3a) The contact is often not there when you first arrive, necessitating either a log off/on, or a quick trip to normal space then supercruise again.
3b) If the contact IS there when you first spawn, it's a dash to get away from the star before they fly past you and drop out inside the star's corona, again necessitating a respawn via either logging or drop SC, go back in again, repeat.
3c) The contact ALWAYS, ALWAYS without fail sends you back to the original system.
4) If you get tailed by 'Incoming Enemies' they are usually stronger than the mission target itself, and it can often happen that if you stop to fight an incoming enemy, that the target will drop as well, or vice versa. To deal with this, you can go back to supercruise where the 'incoming enemy' will interdict you and you can deal with them, but when you do that, 9 times out of 10, the next 'incoming enemy' is spawned, and you get a repeat of the first scenario. Basically, it's best to sit around and wait for the incoming enemies to attack you one by one, then complete the mission. In the unlcuky case that both the target and one of the incoming enemies are hunting you in supercruise, you may unavoidably have to fight 3 full strength enemies. This is rare but is in fact the worst complaint, because it renders the mission very difficult to complete in anything except your tankiest combat ship (I tend to do assassinations in a courier, which should definitely be an option).
5) It still frequently occurs for over 7 months now, that the target has a duplicate, which drops in after the fight begins. They arbitrarily pick a side, sometimes helping you kill your target (their alter egos), before turning on you. Sometimes you have to fight both together.
6) Bonus complaint...Combat missions should not spawn with cargo rewards.
They are really buggy. I haven't even read the OP and the rest of th ethread, but I will now...