Anybody who reads my posts will already know mine and I'm going to restrict myself to just a few lines because otherwise I just will not stop.
Having to use the FSS to scan every body just to get a basic system map. I've actually been to Beagle and back since they introduced it - like an idiot, it's a journey that I actually held off doing for about 6 months because I was waiting for the exploration update, so you can imagine my joy when they dropped it and I discovered that they had completely destroyed the way I used to explore with it. What I'm looking for when I explore is visually interesting planets, whether that be colouration, interesting orbits, close binaries or any combination of those (for example striking colour combinations in close binary planets etc). The number of systems I can potentially check out in a given amount of play time is now about a tenth of what it was before the FSS and it blows today just as hard as it did they day they forced that change on me.
Stopping now because honestly, it's still like a weeping open sore and it will be until the day I stop playing. They absolutely crapped all over what was the most enjoyable aspect of the game for me and I will simply never get past that.
(Note - yeah it's only a game and that's the context the above is written in. It is probably the worst thing I've had done to me by a development team in 35 years of gaming, I certainly can't think of any single change to a game that's ruined so much of it for me. Doesn't mean it's keeping me up at nights or anything and I face more serious problems every single day in real life, I also still play the game, but exploration is a shell of what it used to be and will remain so as long as it takes me ten minutes to get a full picture of what a system with a high number of bodies actually looks like.)
Disclaimer: For literally every other task, the FSS is great. It's great to be able to scan a body to the same level as the old DSS with it, fantastic to be able to check signal sources in systems with it, all that stuff is well thought-out and really adds to the game. It's just the fact that to even know whether I want to check a system out properly, i.e. whether it has anything in it which I might want to examine in any detail, I have to mess about with the FSS just to get a picture of it. I realise that the people who keep spreadsheets of every class 1 gas giant they ever discovered probably love the functionality but that's just not what I groove on and never will be.