JimmiG :
Have they done anything to improve the game or is it still a mindless grind for credits?
There have been numerous improvements and additions in the past 2 years or so, and some of them have been great, others not so much.
If you are talking strictly credits, the game has seen a fair share of methods for acquiring them rapidly, ranging from simply running high paying missions, to borderline exploiting mission allocation to get lots and lots of the same type of missions which you can just complete in one go. Either way, it's much easier now to get the credits to buy one of the end-game ships than it was in 2015.
However the new Engineers update means that instead of credits, you have to focus on acquiring materials (these can't be bought) and then go though different layers of RNG to use them. Some find that to be a grind, others are cool with it. What is certain though is that these mechanics are absolutely necessary if you want to PvP, with ships becoming something like 300% stronger after their upgrade. And if you don't have the expansion, you don't have access to upgrades, period.
If you are talking content in general, my personal opinion is that the game takes one step forward and one step back. There have been many, many small cool features coming with each update, to name a recent few: new station types, passenger mechanics, ship launched fighters, new modules with certain functions, interface improvements, a character creator and many more.
On the flipside, the major gameplay additions which were supposed to add meat to the game have been disappointing. The crafting mechanic turned out to be imbalanced, and actually more of a random scavenger hunt, as I explained above. The multicrew mechanic proved to be nothing more than a gunner mode, sometimes with technical problems. The lore of the game took a beating, being unable to accommodate these simplistic additions within its original low-tech vibe. And there are important areas which have seen very little improvement, or none at all, such as criminality and PvP, or some professions being underdeveloped, or cheating players.
All in all, the game has evolved since its launch, but for me at least, it has not gone in the direction I was hoping it would.