Age of Empires 2 has big tournaments as well, and the campaigns are fairly popular too I think.
For example, getting to the 3rd age in AoE 2 ASAP is basically mandatory, but in AoM you can potentially start attacking from the 2nd age. On top of that, getting to the 3rd age in AoE 2 takes much longer than AoM. So there's basically a whole lot of wasted time at the start of an AoE 2 match.
And Aoe2 is consistently getting official updates, there's 3 Indian and 4 Chinese civs now.