RTS is a genre that's never sat quite right with me. While I do think it has some inherent flaws, which I've touched on in the past, there's also the factor that it just isn't my genre. I don't belong there, nothing about it really says "yes, this is home." I've been getting back into some 4X games lately, though, and I only now realised one of the reasons this is.
Diplomacy's not really a thing in your stock standard Command & Conquers, Age of Empires or Total Wars. The extent of the diplomacy is whether you're killing those guys or ignoring them. Which is fine, really, because that's not really what it's supposed to be about, so that'd just be dead weight. RTS is about ordering, managing and using soldiers, not diplomats.
I bought Civilization V recently, on the other hand, and at a certain point I realised that I was probably spending more time sitting in the diplomacy screen thinking about what to do than I was telling my guys to go and get the other guys. The combat in this, for me, is just a very mechanical reaction to what occurs after diplomacy goes down.
You can really get hit by some surprisingly big decisions. For example, in one game, I was playing with England, America, Germany, and China. I was getting chummy with England, but more or less ignoring everybody else. China is the big player in the match with all the soldiers, everybody else paled in comparison. I was trying to go for a culture victory myself.
Anyway, China declares war on Germany and America soon enough. Germany asks me for help, but, well, I've got no soldiers to spare, do I? And I'm no especially friendly with them. So, I felt a little bad, but I wasn't ready to remove my sole garrisoned units to help them fight a losing war. Shortly afterwards, they got wiped out, which was a little worrying.
Then America asks me for help, too. They have about as many troops as Germany used to, so things weren't looing great, and the result was staring me in the face: help them or ignore genocide. China hasn't noticed me yet, though. They don't feel strongly about me one way or the other.
So, do I risk angering them by helping America, and have them declare war on me? Or do I send aid anyway, despite the risk? I made a bit of a compromise; I sent them some resources. A bit of gold and steel, so they could build a bit more military strength up. Unfortunately, it wasn't enough, and they fell too.
After that came the apex of the match. China approached me directly and asked me to declare war on England and team up to destroy them. That really had me thinking. This was a big call to make. England was my bro, but do I stick to my guns and say no, or do I face probable destruction by angering the Chinese? It was a really telling point. Am I a coward? Do I have to win, or are the ethics of the situation important to me? Is imaginary honour worth imaginary destruction?
I did end up deciding not to betray the crown; England and I stood together and died together, but the conclusion here wasn't really the important part. What was important was the lengthy period of time I was staring the Chinese leader down wondering what on earth I was going to do. That struck a chord with me quite a lot more than whatever white wash scripted moral choice events I hit in Dragon Age.
It also hit me much heavier than any RTS I've played. Don't get me wrong, I've whittled away quite a few hours in Tibeian Sun, Emperor: Battle for Dune and Age of Empires, but all of that was the combat. This sort of diplomatic scenario gave me a backdrop for the ensuing combat engagement. I had reasoning, I had motivation; there was an emotional investment that simply isn't present in RTS most of the time.
This would be like if you ignored the entire film V for Vendetta, but skipped to the end to see the explosions. If you like explosions, and want to see them, then I've no intention of impeding your progress. I'm just the sort of audience that needs a context, a connection to enjoy something - and a lot of the time I find myself questioning the complete lack of that.