Durbatuluk, it just shows that you picked up some skills struggling against the Rheinlanders during the early missions.
The first time I flew a certain one of the earliest campaign missions (the first together with Juni), when we came to a certain spot I died within seconds and did not even know why. After reloading I did find out why and managed to muddle through somehow and was mighty glad that I survived.
A while later - I had beaten the game by then and was busy exploring all the systems and new ships - my brother told me he had problems beating this part of the mission in a Rhino. He had probably seen me flying about in this ship and liked both the enormous firepower and storage capacity for loot, and so he chose this ship. I started a new campaign and found the mission pretty easy, even in a freighter.
And when I played the campaign all over again later - with different ships and different objectives, like trying to fly the story missions back-to-back without freelancing - the only challenge was to solve this mission with a class 1 shield without using any nanos/batts, to save money and also to save the extra five minutes needed for getting a certain good shield before the story takes one to the a place where it is sold anyway ...
So the
perception of difficulty depends very much on the skills a player has picked up already before flying a mission. If you progress too fast then some story missions may appear to be hard, if you progress more slowly (i.e. take time out to explore and learn to fight with your current ship) then the missions will appear like a cakewalk and you'll probably gripe that the freelance missions in the bar are too easy. But there is an easy remedy - you just have to choose a small enough ship to make the missions challenging (outside Liberty anyway).
Also, during my first run through the campaign I gravitated towards the heavy fighters (like many other people, I guess) and regarded the light fighters with disdain after my non-satisfactory experience with the Startracker, which is sold under the pretense that it is a light fighter. Later I decided to do the campaign only using light fighters, just for completeness' sake ... And this completely changed my outlook on light fighters, especially the Patriot and the Drake. Suffice it to say that I am now a fan of the true light fighters, and that beating the campaign for the first time would have been a quite lot easier if I had used them then ...
Since then I have beaten the game both in a Patriot and in a Starflier, which shows that these ships have quite a bit more potential than most people would think at first. And yes, some of the later missions seemed pretty hard in a Starflier.