On Tyrant Mode, all your folks start with one health only, so your kingdom is made up of geriatrics (and Corobo is always the most adorable octogenarian ever).Exactly why I'm not going to try it. Some boss's attacks are unavoidable so I don't see how it's even possible.
Actually, every attack is avoidable (as I've learned the hard way). Some of them are just very, very difficult to dodge. Make sure to never bring more troops than you absolutely need, and use that Guard formation at nearly all times!
He says start. I assume you can still get health upgrades. There are 5 or 6 health upgrades throughout the game--and that's not counting bonuses from equipping items--so your characters won't die from a single hit.
The problem is it just doesn't sound fun. The weakest part of LKS was constantly calling back your characters before enemies attacked. The game would be a real chore if you have to do it even more diligently.
You are correct. Oddly, this makes the game much easier as it progresses, which is the opposite of how it felt the first time. I disagree about it making the game more of a chore, though: while I initially feared the same, it actually forced me to learn the enemies' patterns and weaknesses really well. I'm actually more aggressive now than I was when everyone, including my king, had more health. One exception is that I don't use my scepter after getting the first health edict, as 99/100 that's basically a restart.
Oh, and the final boss is a pain now, since he targets your king quite well. I can't sit here and tell you it's worth the effort, but I loved the game enough to think that the extra challenge was actually a good incentive to replay it.