So if you loved LoL, why don't you play LoL? There are not a huge number of online strategy games for free.
You could check out Age of Empires Online if it's still going...
Yeah literally, it's narrowed down to ONLY Age Of Empires Online. Because everything else is browser-based casual games using time and "energy" to limit you from playing.
Age Of Empires Online is (or was, not sure) a pretty awesome game. I even put money to get the pro greek civilization and skirmish. But you can go pretty well without it. Support for it stopped a while back, and I'm not sure if it is completely shut down. I stopped playing because it felt abandoned, and really it was. But its definitely a treat for a long time for any RTS fan.
I liked picking a commander from the start and developing his skill tree as you leveled vs. regular CoH where you pick from a tree in each game. --- Leader of the Elder Cult of Jiub. Wow. Kenny's a Japanese Princess..
What a horrible fail post from someone who apparently plays SC ironically. Awesome.
speaking of which, starcraft 2 does have a free version. And when the new patch 2.1 comes out, they will be giving the free-to-play people more access to other features of the game --- Warning: The below information will be displayed publicly.