It's not a game killer in any case.
Clearly we have different opinions on what a game killer is. The type of functionality I mentioned are in any good 4X space game. The ship list gets immense late game and you have to click on every ship in the list to find your fleets. This, and using the map to find fleets and uninhabited planets is the height of tedium. Not the mention the inability to quickly find fleets by various criteria, such as fleet strength or logistic points etc., and the same goes for planets and their attributes such as wealth, research and so on. I understand that some people don't like "spreadsheet" screens but they are the best way to quickly manage large empires. I hear people saying "zoom out the map" but the doesn't sort anything so on the largest maps it's not practical.
I'm not saying it's perfect. I'm not even saying it's acceptable. In my opinion, it's neither. That being said, one of your requirements is a planet screen that you can sort by economy, manufacturing strength, or whatever. You don't need to go through the map to look at these things. There's a sort-able planet screen that lets you do that. Unfortunately, you have to re-sort the planets when you return to the screen. Not perfect. Not even close, but it's there.
There's a ship management screen that lets you send all of a type of ship to a location. That comes in handy when you have 100 transports that suddenly need to shift their focus to the other side of the galaxy.
One thing you require is a fleet management screen. That would be super if GC3 had one. If it does, I haven't found it in over 500 hours of game time.
It's not my desire to talk you into buying the game. I have no dog in that fight. Still, we shouldn't complain that it's missing something that's clearly there (the sort-able planet screen). Even if it's not up to standard.
I have to agree as I have been playing Endless Space lately. The ability to turn on governors, combined with the power of the spreadsheet sorts, makes large empire management much easier than GC3. I hope SD and crew fixes this soon.
Endless Space is a great game. It's not as ambitious as GC3, but it's more refined. Bugs persist, but the devs there are very responsive to the gamers. I'm looking forward to ES2.