looking glasses are something that I think would be very tricky in a nonindustrial magic-based world, and magical alternatives would be much more likely, which I thought I covered (in the last sentence as an aside, mind if I fix that?
Tricky and difficult, yes. Impossible, no. All you really need are lenses, which were produced as early as the 13th century.
True, but one would guess that the magical way of developing it would be much easier, which would make research into lenses considerably less important, but it would be good to see a way to improve LoS at a higher tech level then the corresponding magic items, so that really good scouts can be made without using magic, it'd just be harder, and I'm not sure as much effort would be put in, but I could see an accidental invention based on using lenses to craft fine magic items and they would be good to have in the tree to give some way of scouting without magic.
If there is going to be a topographical movement system then there must be some kind of stamina subsystem in place in order to prevent endless chase downs.
I'm pretty sure he implied that, and I like the idea a good bit, it'd add some interesting thought, and this definitely belongs on the tactical map, and it would be nice to be able to have the ability to rush your troops to the battle at the cost of having them arrive tired. It would also be interesting if knights had the speed to chase down light infantry, but because they had to sprint to do it they'd arrive at the battle tired and far less effective, while the light infantry are mostly fresh and therefore have a lot of their inferior combat strength made up for because the knights can't charge as fast. I would absolutely love to see a linked stamina system between tactical and strategic modes, that would be awesome and allow for some very interesting army uses.
Moreover I also think that if a retreating unit drops below 10% strength it should auto disband.
Absolutely, at the very least. I think that unless a unit has been trained, if it is down to less than about 20% it should disband, and if trained stick around but have a morale penalty.
Additionally that calls into question effects on movement due to weather systems.
This is another great reason to have a movement system based on relatively smaller squares, because then rain could be a -1 penalty to movement/-2 in heavy armor (like agincourt) and would be very interesting. The same could go for rough terrain like mountains and woods. A smaller scale would likely result in inanity like civ 2 had (only one I had, sorry, galciv 2 brought me back into 4x from RTS and tabletop wargaming, so I don't get many references) where trying to take a slow unit over mountains meant you had a 1/3 chance of moving at all that turn, which was very annoying and random, when some smaller map squares would've made it a simpler case of just getting a good number fewer moves, but still moving some. I'm tempted to think that weather and terrain modifiers should be based off infantry/cavalry/artillery/beast status and heaviness of armor with either a scaling effect or a flat penalty, but I'm tempted to go flat penalty because the fastest of these things were the least affected, and this would be the same.