To be honest, it is more likely that our future wars will be defensive so infantries are maybe a decent choice.. 
And also, I need to check the correct number in game, but I think we have now ~40-50 knights/cuirs that can be upgraded to cavs if we want. That is a decent basis for the initial strike if we ever get an opportunity for offensive. Cannons+rifle/infantry/trash/(machine guns) can be a decent follow-up force after the surprise is gone while cavs still can fork cities. Hopeful thinking! 
But yes, I think we would be happy to build tanks as 2-movers but we still need a while to get there... 
And also, I need to check the correct number in game, but I think we have now ~40-50 knights/cuirs that can be upgraded to cavs if we want. That is a decent basis for the initial strike if we ever get an opportunity for offensive. Cannons+rifle/infantry/trash/(machine guns) can be a decent follow-up force after the surprise is gone while cavs still can fork cities. Hopeful thinking! But yes, I think we would be happy to build tanks as 2-movers but we still need a while to get there...