In the case of defenses, I understand it's hard to communicate how they affect the battle outcome.
Part of the problem here, as I see it (as a writer and Air Force Vet) is the misappropriation of words & terms. Point Defense, for example, exists specifically a counter to missiles. That is a concept that anyone can understand if they are familiar with the term "point defense" in even a cursory way. The idea that PD would stop a kinetic or beam attack plays against people's expectations and existing knowledge. It would be like going into a restaurant and ordering a pizza, only to receive a hamburger with pepperoni as an additional topping. By misappropriating terms and/or creating new definitions for them, you are making it more difficult for players (new and old alike) to grasp the system. Part of way people begin to understand complex systems is by relying upon shared terms and knowledge. If we use the word "Shield" then we're setting an expectation for what that mechanic does, and that can help players grasp the system faster.
So that's one problem. Another problem is that (thus far) I see no way for the player to control target priority. Range & positioning are two of the most important facets of battle, and yet this system seems to either negate, ignore, or misuse them.
If it were me, I'd be looking at adjusting the combat in a way that factored in player expectations for common terms (like range, fire rate, Point Defense, Shields, etc.) as well as a system that could reasonably translate these common terms into efficient dice rolls. Because at the end of the day, that's what this all boils down to: dice rolls.
I see above the argument that Range should be removed. I could see that if and only if players had a lot more control over target priority (which could then effectively stand in for range and work as a simulation of it), from both an offensive and defensive perspective. Part of the fun of GC3 was building diverse fleets to take advantage of the targeting priority - to build smarter fleets than the AI, so we could ensure our glass cannons weren't getting pummeled. It was possible to build ships into "roles" - tank, support, glass cannon, etc. Escorts were targeted first, and knowing that allowed us to build our own defensive escort packages, as well as understanding how our own offensive-minded ships would attack. If target prioritization is either uncontrollable by the player, or simply to complex to be of any strategic use, then monolithic fleets will become the order of the day. And that will be boring.
The one Idea I do like in here is how shields and armor work, which appears to work more or less like it does everywhere else. Shields absorb damage until they reach zero, then damage is passed on to armor. The nice thing about that system is it's easily understood by nearly everyone and it lends itself nicely to tech, like shield recharge, recharge rate, nanite armor regrowth, etc.
The bugaboo is missiles. As an offensive weapon, fine. They work like beams and kinetics. Hit the shield until it's zero, then hit the armor. I'd like to see point defense only affect missiles, as it would make sense, but it don't know that there's any kind of impetus from the devs or the players to see things implemented that way.
But anyway, that's not the biggest problem. The biggest problems, to me, are range and target priority. If it were me, I might be inclined to try something like this:
First, allow players to assign roles to ship hulls. Hull is completely different from role, and however players want to do it should be up to them, to grant them the freedom to experiment. And how I'd start off is something like this:
Each side of combat has five zones:
Support(5) => Artillery(4) => Guard(3) => Intercept(2) => Assault(1) || Assault <= Intercept <= Guard <= Artillery <= Support
A ship is assigned one of those five roles, thus placing it in that "zone" during combat. This defines the ships targeting behavior and has the nice side effect of being easily represented with a number in code (5,4,3,2,1). It also works as a stand-in for range.
Assault ships attack anything in zones 1 (on each side) and zone 2 (on their own side)
Intercept role attacks anything in zone 2, 3 and 4 on its own side.
Guards attack anything in zones 3 & 4 on their own side.
Supports are ignored. They are the last thing attacked by any role.
With a system like this you don't need any actual ranges, and the concept of Tactical Speed then becomes a facility for moving from one zone to the next. Fighters would have the highest tactical speed, so they could conceptually have the best chance of moving from zone 1 to 4, but they're also the smallest and most easily destroyed. Advancing from one zone to the next could simply be a matter of rolling dice for evasion and tactical speed.
Players and AI could then be free to build ships and fleets as smartly or dumbly as they wanted. Sure, go ahead and put a bunch of glass cannon missile ships in zone 1 with the Assault role, and watch them die right away. Or, give them the Artillery role and let them sit in the back, protected by the rest of the fleet.
Large ships with poor tactical speed wouldn't be able to advance due to the glut of ships in zones 1-3, but if they clear the field then it's easy pickings.
I'm sure there are a lot of potential problems with this sort of design, but I think it also lends well to this particular game and the need for things to be condensed into dice rolls. The problems could probably be worked through. Meanwhile, it seems like there's potential (for the player especially) to build some interesting and functionally diverse fleets.
Because the way I see it, the two most interesting aspects to combat - the two things that can make it complex or simple - is range/positioning & target priority. If you remove those two elements, then you greatly simplify the combat. It's just going to come down to shields being drained until armor comes into play, and weapons that do various DPS. Ship diversity, and in fact fleet diversity, will not be necessary (nor preferred). At that point, you'll just want to build the most robust ships you can with the highest DPS weapons package possible and then slam them together in monolithic fleets. And like I said above: You can do that, but it will be boring.
As for how to show it to the user: Someone above said a picture is worth a thousand words. A 5-zone screen on each side of the battlefield showing how each ship is progressing each round - what its position is, who it's firing at, whether those hits are landing - all of that could be shown in a simple turn-based manner to the player. It would be easy to grasp and understand. Right from the first turn of battle, you'd see where all your ships are positioned, so you'd know: I have 3 ships in the Assault zone 1, and 2 ships in Intercept zone, and 3 ships in Guardian zone with beam weapons, and 2 glass cannons in the Artillery zone with missiles, and a support ship in back. Bang. Easy peasy. Watching the battle progress - watching the ships move through the zones - would be kinda fun. It would be like watching a time-lapse of Civ/Old World/Desperados. Hell, I bet that would be really addicting to watch.