The Lopsidedness of this discussion is incredible.
1 vote for the OP as opposed to the 11 votes the first reaction saying no gets.
I could say it's a pirate game, it's an open world PvPvE game again like so many times before and so many people before me (and with this I technically have)
But I see you complain about people killing you as soon as you get in range. I kinda get this a lot.
While people see me as a PvP player on the forums (mostly because I defend the status quo) I'm really passive. There's one thing I won't ever let anyone do and that's sneak up on me.
I don't really care that you fly an alliance flag, I don't care that your intentions are good. If you approach my ship and don't react to my calls for a diversion of your course and you don't even utter a single word you will get shot out of the water. It's nothing personal but it's just me and my crew defending our loot, our ship and our supplies.
I've had many encounters where we sunk a ship and they complain about being friendly. If you're friendly don't stay silent for ages and don't sail directly into the broadside of a galleon.
Your "Karma" system would do more harm then good. The game isn't an omnipotent system that knows everything people are thinking. It doesn't know that I shot first in self defense. So why would I deserve Kraken Megladon and Skeleton ship attacks for defending myself? The same goes for bounty systems, it's not in the game because it can and will be abused and it would break most of the game.
It sounds to me like you've got some things yet to learn. My advice is to group up for a change. Get together with some fresh strangers and start a galleon. Get a feel for this vessel and it's handling, try a brigantine see how it functions as well, you'll encounter some Solo sloopers who will kick you in the rear quarters while being 1v4. Solo play is an afterthought, the sloop wasn't even part of the game untill players told Rare that they wanted to play with 2 or even by themselves. It's not the way the game was meant to be played and I don't think any change would ever be made in that regard.
I'm not saying you should stop solo slooping. I'm saying you should at least try to play the game with others and otherwise man up a bit and accept that you chose to be alone versus crews of 2/3/4