At what point is it considered "grinding" though, and are we sure it's actually necessary? Is it considered grinding if you autoresolve a handful of looter/bandit fights every so often?
In my experience, it doesn't really take all that long to bounce back from a total party wipe. What I do is grab all the mercenaries I can from towns (including armed traders), and pull as many troops as I can from a pass of my faction's settlements, autoresolving any bandits I catch along the way. Then, once I reach the enemy's borders, I run around to a couple villages and force them to give me recruits, which triggers a battle with the militia, but doesn't result in relations losses unless you proceed to actually raid them. Militias are good troops to cut your party's teeth on, and after a few of those I can usually return to fighting lords. As others have said, if you own a fief you can also puill some garrison troops out to supplement your forces. All of that takes around 15-25 minutes, and it usually doesn't even feel like grinding to me.
That said, does the gameplay loop eventually get tedious? Sure, but to me the game is still fun in moderation.