@OP - It sounds like you enjoy the kind of strategy games that big developers aren't making anymore. It sounds like you enjoy the strategy aspect, but don't like excessive micromanagement, and you also don't like over-complexity. Unfortunately, most of the "grand scale" strategy games being developed these days that don't require ridiculous amounts of micro are extremely complex to compensate.
There are some games that fall into the "middle-ground" category however, most of them being mods made by third parties.
Company of Heroes - The CoH basegame (+expansions) by itself is good, but it suffers from several problems. The AI is quite lacklaster, and the gameplay itself leaves something to be desired. The builds/skill trees aren't overly complex, but you find yourself taking the same routes over and over, and the game just seems like it could be a lot better. Most of the people who play online are hardcore players who have been around for years, so that option is more or less out as well.
There are dozens of mods for this game, but the two I have found which are the most noteworthy, and give the kind of gameplay it seems you're looking for are:
Blitzkrieg - This may as well be a new expansion to the game. It takes the rather simple Commander Trees and makes them much more complex. All 4 factions are completely redone, while still attempting to keep their original flavor. The combat is EXTREMELY realistic, it's probably what Relic/THQ was going for when they actually made the game, but never quite achieved. In fact, it's possibly realistic to a fault. Your infantry are incredibly vulnerable. Each member of any given squad will die if they are hit by any type of ammunition basically, which means that forward reconnaissance and heavy use of cover is incredibly important for survival. Heavy machine gun squads, Snipers, and Mortar Teams are a lot more powerful than before, but also more expensive, and have about the same effectiveness that you would expect in real war. In other words, they absolutely demolish squads of infantry if used correctly.
Probably the most enjoyable aspect of this mod is the redone vehicles/tanks aspect. Tanks actually feel like tanks. If any tank comes in range of any infantry squad in the open it will simply begin mowing it down. Though tanks are basically invulnerable to rifle fire, they still die in 1 or 2 shots to other Tanks (depending on their strength). They just feel much more authentic and enjoyable than the vCoH tanks, which seemed more like the product of a balance triangle than the actual beasts of battle you would expect. Another really interesting aspect of the tank rebalance is that it tries to be true to the way tanks actually were in WW2. In other words, if the Germans get an overly expensive Tiger Tank, you should probably just crawl into a corner in hide, or hope you can somehow flank it/surround it because the Allied technology just isn't up to snuff in that regard.
My second favorite thing about this mod are the visuals and sound effects. They've done an extremely good job with that. The map zooms out much further than vCoH, giving you a great "Commander Perspective", instead of feeling claustrophobic like the original game. Everything makes you feel very connected on the battlefield, and overall, it's a huge step up from the original game, even if I don't agree with all the decisions they've made on it (some things are overly complex).
Modern Combat - As the name says, takes the Company of Heroes concept, and rehauls the entire game into a modern-day military simulator. Interestingly, the two factions become the American and the Chinese.
This mod is my favorite so far. Partly because I'm not a big fan of the WW2-era combat, but also partly because the mod is much more simplified than the Blitzkrieg mod. I've played 3 multiplayer games with this mod against people so far, and it has been some of the most fun I've ever had in video gaming...and I've been playing games for even longer than you have. The combat is extremely visceral, the units and strategies are very intuitive, and the Commander Trees aren't overly complex like in Blitzkrieg. However, it does have some drawbacks compared to Blitz. The camera isn't zoomed out, so it stays kind of claustraphobic (though considering the intense, visceral combat they were going for, this was probably intentional). The sound and graphical effects certainly aren't as good. There are only 2 factions instead of 4, which kills some of the diversity and replayability. And while the simplicity of the entire system greatly improves and streamlines the game while playing, it also kills some of the long-term replayability as well.
Even still, this is a freaking amazing mod; they both are. I would say in terms of balance and pvp, Modern Combat comes out on top with flying colors, but in terms of replayability and environment, Blitzkrieg wins with flying colors. They are both still being actively developed, though the MC site is temporarily down
You can install both of these mods simultaneously (they have different shortcuts). I would highly recommend it to anybody who enjoys Strategy Games.
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Supreme Commander 2 + Expansion - Somehow, many RTS gamers seem to have missed this one. But if you haven't tried it, it seems like it would be right down your alley. It's basically the perfect combination of micromanagement and grand-strategy on an epic scale. It's still being actively developed by some of the old team. A new patch was released not that long ago. The game is like $12.50 on Steam with the expansion. There's also a demo. I probably won't go into that much more detail because you have to try it.
However, it suffers from some of the same problems as vCoH - crappy AI, hardcore players, and not enough replayability (though a lot more than vCoH to be fair).
Revamp Mod- Basically the only good SC2 mod out there, but to be fair, it's freaking fantastic. It basically makes the game into a hybrid of SupCom 1 and 2, keeping the best aspects of both games intact. If you like original SupCom2, you'll like this mod. My friends and I are always looking for more people to play it.
The current patch (v1.1) is more of a "proof of concept" more than anything. Though it's fairly well-balanced, and certainly playable (and definitely a lot more fun than the vanilla game), the first major patch for the game is the next one (v1.2) which still doesn't have a definite release date. However, when that patch comes out, it will go from being a great mod, to most likely becoming godlike.
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Since it sounds like you aren't afraid of the first-person genre, let me recommend
Natural Selection 2 as well. I already made a
thread about this, but this is the best FPS/RTS hybrid that has come out in a LONG time. Even if you aren't the traditional FPS fan, it will still probably appeal to you. The "Commander" mode is unlike anything I've seen in any other game, where you get to command actual players in real time. The gritty sci-fi humans vs. aliens combat is the best you will find in any game. (Well any FPS game anyway, Starcraft 2's Human vs. Alien combat is pretty bad ass).
If you're not a big FPS fan, and aren't playing the Commander role, there are unique roles you can take in game that aren't your typical "twitch shooter" which are still fun and contribute to your team. The Gorge is a good example. The Gorge is the support lifeform for the aliens, who can heal allies, create living turrets, breed a small vicious alien army, and bombard human structures from afar.
The game uses its own engine and is constantly being developed. It is made from the ground-up to be modded, and I highly recommend it to anybody with even a cursory interest in the Sci-Fi or RTS genre.
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All of those games fit into the category of the kinds of things I LOVE to play:
1. Huge strategy aspect
2. Not micro-intensive
3. Not overly complicated
4. Good AI or enjoyable PVP gameplay
5. Lots of replayability
6. Very moddable
7. Still being developed
Two more upcoming games that you may be interested that fit into this category:
Wargame: Airland BattlePlanetary AnnihilationAdd me on Steam as Wingflier if you're interested in playing any of these with my friends and I.