Hmmmm I was planning to check this out someday. The issue is that I don't use my PC for gaming anymore these days specially not with mouse and keyboard. Heck my setup doesn't really work for mouse and keyboard
I've been playing on a couch with just a mouse if that'd work with your setup.
In the old game your empire's border expanded as your planets grew in power and you built frontier outposts along the border. Placing frontier outposts was very expensive.
In the new game your empire's border never expands automatically. Instead you have to build a frontier outpost in a star system to add it to your empire. Frontier outposts are now pretty cheap.
Also in the old game you had 3 different types of warp tech. Now everyone only has 1 specific type of warp and the others are only used in rare cases. It's a cool change because it allows you to build blockades and focus on reinforcing borders since all enemies have to come from the outside, but the original thing was more hectic and fast paced.
In general the updates have just really slowed the game down. On one hand it's a good thing since you now have more control and it's better balanced as a strategy game but on the other hand it's even less casual.