Not quite like that. Each weapon type is countered by a defence, so lasers are countered by shields. This means trhat you will need to design ships to counter the opponent you are currently fighting. So for example, if the Drengin attacked you and turn out to focus on laser technology, you should equip your ships with extra shield generators to neutralise them.

It's not planned in the r-p-s. It's planned to provide variety...

You and the Drengin start as close neighbors. You are the humans, with the starting weapon tech Mass Driver 1 (MD1) and defense tech Armor 1 (A1). The Drengin start with weapon tech Missile 1 (M1) and defense tech Point Defense 1 (PD1). It's not long before your two empires are engaged in battle with each other, because the only usable worlds in reach of your little corner of the map is between your two home worlds. Soon, the marines are invading worlds, and your star ships are killing their transports and then all the combat craft are trying to kill each other. With no tech advantage, then the winner of any fight is going to be whoever attacks first... neither of you can defend well against the others weapons. What do you do? Should you research PD1 and put that on your ships so they survive their engagements with the Drengin more often? That's the natural response. You get PD1, and start using it. Your new fighting ships come off the production line with MD1 and PD1. What are the Drengin doing? Are they researching how to defend against you, or just do more damage? That's the arms race. In a MP environment, that could get really interesting. But as we are talking AI (code), it probably just research M2, then PD2. Since the wrong defense is 1/2 as good as the proper defense, that makes it easy on the AI. It will just have a "favorite" weapon and a "favorite" defense, and that's what it grabs, and that is what it puts on its ships.

Fear not. That will still make the game "interesting". Consider our scenario, slightly advanced. The Drengin empire is no more. You've conquered it, and are expanding out. Your top ships are outfitted with MD3 and PD2s. You come in contact with the Altarians, who are just finishing crushing Iconians. The Altarians are outfitted with MD3 and A3. The Iconians are using weapon tech Beams 3 (B3) and defense tech Shield 3 (S3). If you use your current navy to slam into the Altarians weak backside flank, you'll manage to grab a couple of their worlds before they get their navy running your way. So you go for it ( you sneaky strategists you!). But when your ships and the Altarians start facing off, your current ships are coming out much the worse... they have the perfect defense for your attack. Whoopsie! And you let your perfect defense for their attack slide. Of course, your new ships are designed with MD3 and A1. Why? Because its cheaper to put the A1 on then the PD2 you had, and just as effective. (Will you put both on your ship? A1 + PD2 = A2. Better survivability, but what do you give up to get that on your ships? Choices, choices) So, you'll be busy doing what, research wise? You can raise your weapon tech to MD4, but the Altarian defense of A3 is still going to be highly effective against your weapons. Or, you can go for the fast research path of another weapon tech. It is obviously wiser to research A2 rather then PD3 to improve your ships versus the Atlarian warships (Smaller tech = faster reached).

I'm more in favor of just 2 categories, Energy and Kinetic. It doesn't provide the chance that you will have a fleet of ships that are heavy into 2 defenses, and have an outbreak event where part of your empire turns into something else, and the pod people that took it over have high attack tech in the one area you have nothing to defend with. However, it would be easier on the AI to handle. We humans will find the exploits and min/maxxing of the tri-category system quickly. The AI won't until SD can learn them (probably from us) and then code them in for the AI.

In truth, we humans will make mixed craft. Because 2 defenses will always be better then one. And then we will add in the 3rd. Because that's even better then the 2. So our defense designs won't be specialized, except under rare circumstances (ie, the start). What about weaponry? 2 categories are better then one. So guess what that means for min/maxing?

Its fairly predicatable what people will do. If we do it, eventually the AI will have to be modified to take that into account. If everyone (us and the AI) is flying around with ships with evenly split attack and defense, that will defeat the purpose of having multiple categories quickly. So I truly expect the entire combat system to be changed between now and "production". But hey, I'm probably lost in space again.

Fuzzy, the Rock-Paper-Siccsors analogy just doesn't really apply to GCII's combat system. Each of the three weapon types functions in exactly the same way, if a ship had no defences at all it would be equally vulnerable to all three weapons. The system simply means that if you focus on a weapon type which your opponent is poorly equiped to defend against,. you at an advantage. Likewise, if you are attacked by a weapon type you have poor defences against you are in trouble.

There is no mechanic where unit X beats unit Y but is beaten by unit Z which is beaten by unit Y. Or whatever. In GCII terms, laser tech isn't superior to mass driver but vulnerable to mssile. They are all equal, it's all about how you combine them to overpower your opponents configuration.