DK, in my opinion you make some great observations and a few lesser ones as well :-)
Firstly, further restricting the capabilities of second chars (no lordship or whatever) will only worsen the drone aspect, not lessen. There are in fact 2 problems with dual characters on the same island. In many cases they are a drone to serve in the army of the primary character so his realm becomes stronger and his power is more secure. Secondly is when you do go into 2 different realms, it's often difficult to have these chars work against each other, leaving extremely strong ties between nations. Especially when both chars become important (Dukes or whatever). So in this regard, I don't really agree with your suggestion.
1: Old characters
- Personally I would have a different solution: Introduce mortality for all chars and make it more likely as the char gets older. It's rather rediculous to see 110 year olds lead a charge of cavalry don't you think? This would provide more opportunities in the game as well as Dukes and all (often older chars) die and leave a space for another to fill. I do agree though that the aging for the hours could start a bit later. But it makes sense that once you're like 60, it takes more time to do some things, which means you have less hours available. If it really bothers someone, they can always retire the char and start a fresh.
2: I agree entirely on this point.
3: I agree mostly on this one as well. Perhaps it's an option to make the priest similar to an adventurer with very limited impact directly via game mechanics. The religion game is almost dead, because most people don't want to 'sacrifice' a char for this. It would be interesting to get it back to life again and I think this may very well help.
