The game has been dead a long time. The engine is just so horrid that working at the edges means nothing. There is like 2 second input lag built into the late game because of some horrid optimization issues.
Watching "high-level" players is more like watching the WSOP. There is no fine micro-control. The luckiest person wins unless there is some weird meta strat that is OP (read AEC spam last patch).
Better to let this game die and then hope COH3 hopefully fixes things like 5 years from now.
I've never noticed any input lag, and I find your dismissal of micro and skill among top players a bit much. Maybe you're having some driver issues, or running the game at too high video settings for the late game action leading to input lag?