If you look for real time strategy then the choices we have right now are nowhere near the quality of what we had 15 years ago.
Most modern strategy games are overly complex, take forever to get into and are overwrought in ways that makes them just not enjoyable.
StarCraft 2 is probably the most recent major RTS release, and it's not particularly active despite being an excellent game. The issue with the RTS genre is it's been superceded by two other genres. The people who want to play RTS games are playing MOBAs like Lol or Dota, or have moved to city building games which have had an explosion in popularity.
That said, Dawn of War 3 was released last year, the Total War, and Anno series still exist, StarCraft is still receiving updates, albeit infrequently, and there's a handful of indie games that scratch that itch
It's a small hardcore group of people that still play it but I find that stands out as the most innovating RTS that I have ever played.
There's nothing quite like having to negotiate with your peons to chop wood in exchange for better weapons later in the game.
Wrt BZ2 a remastered version is available on GoG / steam. A few of the original developers have kept the game patched and compatible with todays hardware / software.
There's a new RTS-FPS hybrid which is being developed currently on Early Access. It's taking the genre in a way is more similar to Battlezone in a sense that you actually train AI units rather than it being 100% human players on the field. It's a 5v5 , and commander filled the battlefield with trained AI mobs while player are much similar to warcraft3 hero.
http://store.steampowered.com/app/505740/Eximius_Seize_the_F...
Discord : discord.gg/ammoboxstudios.com
Age of Empires is being revived with the classic, well-proven look and feel, with upgraded graphics and new campaigns. Settlers is being revived with the classic gameplay (I hope) and not the AoE style gameplay.
There are several other games expected to be released this year or next and look like excellent candidates for being top-of-the-line strategy and city-building games. I hope at least some of them live up to the promos and hype.
Planet Coaster if you want a decent Rollercoaster Tycoon successor.