Stellaris didn't launch as a bad game, just a game that hadn't figured out what it was. While the new Heinlein patch helps Stellaris become more coherent, it still doesn't quite work.
There's a host of small improvements that do make the game easier to parse. When you're beefing up your military, the ships fly over to your rally point, and instead of creating 3rd, 4th, and 5th fleets you have to manually merge. Information on how much influence is needed to colonize a nearby planet is now contained in a menu, which saves players from building an unnecessary colony ship. These changes were sorely needed: when a larger empire is kissing your borders and mounting an army, you don't want to wonder where the hell all your ships are.
But these elements are so small and so basic that I couldn't help but wonder why they weren't present to begin with. It's nice that the ships have all been balanced so that each type is necessary in a fleet, but why haven't they always been that way? It's really good that Alliances have been removed in favour of Federations, but the two mechanics were always redundant. The changes are all necessary but they seem like no brainers.
What's most frustrating is that Diplomacy, which has always been a muddle, still doesn't feel as dynamic or exciting as it does in other 4X games like Civilisation or Paradox's own Crusader Kings II. While Stellaris has never sought to be a complex or esoteric game, that lack of complication means that the interesting and hilarious stories that define the genre just don't happen.
Because Diplomacy is still so dependent on the ethics you roll, it makes relationships between empires feel stagnant and predictable. If your ethics match, you'll get along fine. You'll still never be able to have any kind of relationship with Xenophobes, and Peaceful empires will always clash with Militaristic ones. There's nothing unexpected about Stellaris, which makes different playthroughs with different kinds of races all blur together, even with the latest update. You can make other empires that like you like you more, or empires that hate you really hate you, but there's never any surprise. Crusader Kings II could shock you by catching your son in a plot to have you assassinated or having relationships with other nations change wildly, but when you make first contact with a new empire in Stellaris you pretty much know how it's going to go.
Stellaris is meant to be approachable to people newer to the genre, but smoothing those edges has made the game uninteresting. Until Paradox can find a way to add that complication back in, Stellaris will still feel like a chore to play.
There's so much potential in Stellaris to be a good game that sometimes it's easy to overlook how it doesn't come together. But it just doesn't. The changes made in the Heinlein patch are all good ones, but the update doesn't add what the game needs. Stellaris needs to feel alive, and instead it continues to be a spreadsheet with nice UI.