RE:- unit replenishment - I actually prefer the new system - it means you can't replenish veteran units in one turn, and if you have a costly battle, you're progress is impeded for a long time (esp' if you're not based in a high-end castle) whilst your units recover numbers. Replenishment should of course be a function of money and time, but on balance time seems to work better. Also means that the AI doesn't turn up with 20 unit armies, half the units of which have 5 men in them, like it used to. Agree that not being able to upgrade veteran units with armour and weapon upgrades is irritating though.

RE:- castle improvement - well, actually you could build a fortress next to a village if you wanted to, and ship in the blacksmiths etc. to make them work - infrastructure isn't necessarily dependant on high population. Plus time taken to build all those upgrades means you've got a probably got a fairly well developed region by the time you get them anyway. Food is a bit wacko though, as you can build high end farms in a barren region and get just as much food excess as doing the same in a fertile one - just less income.