I figured I'd make a list of some (generally) small suggestions to fix most of the blatant issues the game currently has:
1) Shield delay. When shielding add a 2 minute delay before it actually activates. This would fix alot of the shield abuse that is currently happening.
2) Make attacking lower castle players be inversely less rewarding then attacking higher castle levels. For instance, attacking someone much lower would give you a way lesser percentage of their resources. The same could apply for dueling much lower players (in terms of honor gained). This would both help newbies and decrease the amount of farming.
3) Make the dueling advantage be based on the percentage of stats you have more then the enemy instead of just based on having absolutely more stats.
4) Reinstating an alliance directly after it has been dropped should not be possible for quite some time, in example 24 hours. There should also be a window of in example 8 hours before the next election when all alliances automatically get dropped.
5) Nerf Jacques. It is not a good thing if players get a huge advantage out of the gate by just getting this single hero.
6) Add in an option to reset your hero so players that made huge mistakes in that area have a chance to recover (not XP, just ability points and stats).
7) Only allow the members of the house that got attacked to revenge someone in the capitol. This will allow smaller kingdoms to have a fighting chance.
8) Don't allow players under a certain amount of wall to still attack other castles. It is really weird that players without any wall can still do hundreds of attacks and that they don't really need to shield because they don't have enough wall to destroy. Maybe also have a set minimum of how many resources you take if someone has no wall (it is really weird you can't take any resources if their wall is gone ).
9) Explicitly state that secondary accounts are not allowed and add some mechanics to deal with people if they do use them.
10) More options in setting your garrison / tactics for your troops to use. The game is way too much decided by whoever has the most stats.
I probably forgot some, but I think these are the most important one's .