People host private WoW servers, and some have 2x/3x/4x XP rates and altered drops and stuff like that.
I've never heard anyone say it's dangerous but I suppose the fear isn't unfounded. They generally run on outdated clients that wouldn't have the same level of security as retail, and then there's torrenting your client in the first place...
There's some really cool ones out there, though, and I'd recommend trying them if you want a free way to experience WoW again. There's one called Ascension where your character is all of the classes at once and you can get really creative with different builds.
RTS just fell out of favour and isn't popular as a genre anymore. StarCraft was the only one that endured, and even that was a niche interest. If the genre had any appeal then someone else would have taken up the mantle (as we saw with MobA's).
Subscription gaming was going to happen regardless.
I'm reading Jason Scheier's book about Blizzard and it specifically says that subscriptions were already the norm for MMOs. In fact, battle.net was revolutionary at the time because it was free while a lot of contemporary systems charged by the hour