Atypical RTS: SC. We've all played it. It's balanced very well. It's the unofficial national sport of a country. Not only is that something no other RTS can claim, no other game can say that, period.
"Cradle to the Grave" RTS: Either Civilizations (Take your pick for which one) or Age of Empires 2 or 3. Both do it very well. Civ takes it to an absolutely massive scale. AoE keeps it within a single sitting. Games like Rise of Nations and Empire Earth get no mention for broken balance and game play.
Everything Else: Toss up- WC3 does a good job bridging genres and has 3rd party support that's unprecedented, but I have a soft spot in my heart for the Homeworld series.
Legends: Dune 2. If you've played an RTS it's got something that was first seen in Dune.
CoH is a fun game on paper, but as is the case in most of Relics games it is truly stillborn because of ridiculous balance issues and bugs that are really game breaking when you try to play it seriously in any capacity. If you don't know what I mean look no further than the bugs and balance issues associated with the three most recent, significant patches:
1) MGs changing windows instantly. Status: Bandaid fixed. Now instead of having them be able to hold off an entire army's infantry with one unit they have a set window changing timer, which is even more problematic because now you can't control the damn thing at all.
2) MGs out of buildings can't be told to manually target enemies- they'll unpack the weapon, then repack it, then unpack it against and start firing. Guess what your opponent will do?
3) Burst fire bug. Many units had an issue where if a shot hit and killed a target they'd immediately reload and fire again. Not a huge issue in most cases, now imagine a unit like the Ostwind Flak Panzer, which fires in quick succession normally and has a clip size of 6 rounds or so. Status: Not fixed! Ostwinds are the only unit it still applies to, but it's still there.
4) T17's. Used to be retarded. 3 shot clips, high accuracy, and an almost guaranteed kill against any infantry it landed on. Vet 1 granted them most of the perks their normal unit (M8) replacement had to spend munitions on to get. Broken as hell.
Status: fixed. Kind of. They still fuck up the PE.
5) British as a whole faction are broken. If they don't abuse things that are recognized almost universally as OP then they get boned by other factions abusing things in similar fashion.
6) PE as a faction are broken. Playing and winning against the PE is insanely easy, especially when their only infantry unit costs as much to reinforce as heavy, elite infantry. Oh, and a single strafing run can wipe them all out.
