I don't like how combat works right now. It feels oversimplified compared to GC3.
In GC3, you had to decide whether you wanted you wanted your military ship modules to be stronger, miniaturized, or cheaper. And you could mix and match which ones you chose, so you could get improved beams and cheaper point defense, for instance. This provided a lot of strategic depth to the game that we are now missing.
Additionally, I feel like GC4 has taken a step back in the use ship roles. They're still part of the game, but they aren't explained anywhere. As a result, it's almost like they don't exist for new players. Another factor is that you can no longer upgrade your ships. One great thing about GC3 is that if you had old ship you didn't have a use for, you pay credits to upgrade it, and sometimes this even involved changing the ship role. This meant you could, for example, upgrade your interceptors to change them into guardians so that you could incorporate them into a defensive fleet and they wouldn't uselessly die at the start of the battle. In GC4, once a ship has a role, it's locked in. On top all this, there's the problem that if you get a military ship as a reward for surveying a ship graveyard, you actually have no way to figure out what it's role is. In combination with the fact you can't upgrade ships, this makes it very hard build a fleet strategically.
At first, when we got the Battle Viewer back, I was really excited to how combat mechanics were working. But now in my games, I almost always just ignore the battle viewer because it doesn't tell me anything useful. I'm not assembling a fleet of highly coordinated ships like I was in GC3. I'm either putting together a hodge-podge of ships to fend off attack, or I'm pummeling my enemy because I have superior weapons technology and production capacity. In neither case do I get to make any relevant or interesting decisions about the compositions of my fleets. (Yes, there's the choice of beams/missiles/kinetic, but right now with missiles being superior that doesn't feel like much of a choice, and in any case the weapons you build are dictated by the kind of resources you have.)
As a side note, I like the ability to click on the battle alert in the top left and get to the battle viewer again. I feel like since we have that ability, we no longer need the battle viewer to pop up automatically. It gets annoying having to dismiss the battle viewer each time you attack a pirate or survey a ship graveyard.
There's also a problem I've found with the battles-taking-more-than-one-turn thing. If you have smaller ships at the forefront and slower ships at the back, the battle can be over before a big ship even gets into the fight. This happened to me the other day when I was trying to take down a precursor shipyard. I had a medium-hull carrier commander ship that was carrying four interceptors. I had some small-hull ship as well. Because the designation of the carrier ship was "support" it started way in the back, and the interceptors of course started way in the front. The carrier ship had 32 missile attack (the interceptors I believe used beams), so I thought we would make quick work of the precursor shipyard. What actually happened was the interceptors fired a few rounds, some of the small hull ships got off a shot, and then the battle was over. The precursor shipyard took maybe 1/5 of its health in damage and I lost an interceptor. (I'm not sure currently if these are replaced, or how that works.) The other annoying thing was the "Battle Prediction" was total victory. So Battle Predictions right now aren't taking into consideration the turn limit.
I hope they fix combat so I can start crushing my enemies. I've been playing mostly peacefully and going for Prestige victory because warfare just doesn't interest me at all right now.