At the moment, the tutorials are not very thorough, but as far as i know, they are basically only placeholders, too, like most of the stuff we are playing. For example, they completely fail to mention the most important commands, "attack" and "defend", of which there should always be one on the map, because it keeps your fleet sticking together. It wouldn't make a lot of sense to produce lengthy and complete tutorials of an alpha build where lots of core mechanics are still subject to change.
It is important that starfarer is pretty much mostly about piloting a ship, and only a bit about fleet control. I don't really think it will ever be overly interesting to play it only on the tactical screen, but that could just be my opinion. However, i gave it a try, and you can win the mission you mentioned by simply giving an assault/defend order somewhere, and putting your destroyer on autopilot. Your ships will usually blow up the carrier, and then continue to slowly mop up the rest of the ships. I must also say that when piloting the destroyer myself, i did not really have a problem killing the assault frigates, i just shot at anything that got too close to me (focussing the carrier a bit to stop the fighters from replenishing)
As far as i know, the escort commands at the moment don't work really well, and basically should not be used.
If you have half damage enabled, which it is by default, you can only ever gain half the points in any mission.
However, you have some good points, some things in this game are not quite fleshed out enough for a complete release. Tutorials are missing, the campaign beginning is quite steep, and there could be a lot more to teach new players how the game is supposed to work. But you have to realize that this is not a complete release, it is an Alpha preview, and you were told so upon buying it. I, for one, am completely satisfied with what i got so far, and hope that it keeps getting better. That will probably also involve smoothing out the start for beginners. The game itself is not actually hard by itself, just the choice of missions that are in the build is, and there is a lack of a good tutorial. Give the enemy less ships, and you have an easier mission, that is not something that is so out of the way that it would change the general concept of the game.
I also didn't find the missions in the game that hard. (Sure, some are, but they are described as "Hard" or "Impossible", so i expect them to be hard. You just need to know two things: Set an assault order, and put PD weaponry on autofire, and they are suddenly much easier.