I will often have 4-5 armies rolling across the enemy at a time.

If not more.

Big countries with big armies need more than one general, and typically have more than one front to cover. Play Byz empire, you're see what I mean, lol, I got almost as many 'fronts' as I have provinces. Catholics all over West and North, Muslims to the East and South.
-Constant- war barely keeps my tradition over 60 with me having on average 1 general at a time. And I'm probably killing 50-100k enemy forces per year. You'd think I'd depopulate the whole place eventually, just removing a generation of people from existance at that rate. Kill country X's 15k troops, and his 2 buddies, wipe them out also, etc. Next year, fighting some other alliance, sieging like a mad man to try and finish every war before January so I can get my magistrates without the war nerf.
Oh, and I'm not even really expanding much, don't want the infamy... Just doing this to maintain that 60 army tradition, lol, nevermind trying to reach 100.