I like ideas 1 and 3. Could prove interesting, but you kind of forgot to mention what exactly happens as a fief becomes more corrupted or more loyal.
5 and 6 will completely screw over small clans/alliances and make the game less fun for players in general. Let's say you're a gigantic clan like DRZ, Fallen, LLJK, or Grey. And you decide to go pick on the smallest clan next to you. They're going to need help and desperately. However, the majority of the people next to them are your gigantic clan. So unless by some luck, they can get every other clan around them to help out, they're more doomed than they originally were. And if your big clan doesn't really need extra fiefs, it can just promise little small clan's fiefs to any nearby clans that help out. Not to mention that anybody who is generally new to Strategus and doesn't have any connections will mostly likely be experiencing their Strat battles through AI villages. If AI villages suddenly start prioritizing whoever's closest, they'll be missing out even more.
2 is debatable, but personally, I think it's a bad idea. At best, it's an attempt to punish larger clans. But in the end, it just discourages letting others into battles. Fallen would be at a huge advantage if something like this ever went through. We have a massive amount of EU players and a massive amount of NA players. All we have to do is determine what time zone the majority of an enemy is in and attack them during the other time zone. We can get plenty to show at any time. Chances are the enemy won't be able to get many of their own to show during the time we choose and will have faction mandatory slots that they just can't fill. However, even that won't really matter as what will actually happen if this goes through is all big factions will split up into smaller factions to completely invalidate any extra programming done.
4 I can go either way on, but this will also be quickly invalidated as people can just switch factions.
Also, as a side note, your title of slowing strat down is going to immediately put people in a skeptical mood of your post before they even read it. Strat is pretty freaking slow as it is