I would hope you would be limited to 1 vote per clan and 1 vote per fief.
Preferential voting isn't about it being democratic it's about it being political hard to over run just by numbers alone. Talk about a fucking nightmare to wrangle, if you were to try and do a clandestine back door voting deal with another clan people being able to preference you to death would make it pretty hard.
If the UIF vote as one giant block to secure huge sections of the map right out the gate and everyone else can just go on the forums and right up a list of fiefs and just say vote 1 for yourself vote 2 this other guy then it can negate the UIF's power to vote as a giant block.
The power of large groups isn't just that they are large it's that there are lots of smaller groups that are self interested and will be overwhelmed really easily, but if you have a preference system in place as well you have to do more than just be big to win because a whole group of smaller self interested groups can come together and say "I'm voting for myself but if I can win it I'm going to vote for the Nords to have it."
So basically people can put up a claim, talk to everyone interested in it, do a preference deal and cock block a giant clan from claiming half the map.
The devs say there will be "no ai fiefs" it's going to be pretty hard to do if everyone has just 1 vote. There is the potential to have fiefs left idel which wouldn't be the end of the world, it would also give clans like the Grey's a huge advantage over everyone else.
Yes seeing as the UIF powerblock is the biggest, and everyone in there just votes their fiefs #1 and their allies #1 and their allies reciprocate, how is that any sifferent than a big clan just voting for territories they want and ignoring other territories which it has brokered with allies. It isn't like all the non-UIF clans are going to sit down and say 'hmmm lets support shitfaction 1 just to piss off the greys!"
With preferential voting the UIF has the biggest opportunity to fuck over smaller clans just because they will have more people to vote for both the fiefs they want the fiefs they dont want, ensuring that they get a nice continuous block while everyone else has to deal with territories spread out across the world.
Why should a big clan not be allowed to say hey we are going to get 50 people to vote for us on this fief because we want it really bad or because a bug makes it impossible to siege, if they try and spread their bids too far apart then they will not be able to claim as much territory as they would like when a little faction manages to put all 10 of their members into one fief and then all of their votes are doubled or whatever. Being inside the fief supposedly gives you a large advantage, so it isn't just 1 to 1.
Honestly the way I see it happening is the big clans will want to prioritize on towns and castles, this will allow small clans to grab villages and try and hold on for dear life. Or a particularly savvy small clan that gets a good opportunity with the spawns can dumb all of their votes onto a single castle or town while a large clan gets the surrounding villages and will have to siege to get it.
You should stop looking at this as an election and more like a game of Monopoly, if you land on a space you can buy it, if you don't want to buy it you auction it off to the rest of the players. Naturally some players will broker a trading deals to try and maintain blocks, so that they can build houses and hotels to continue the analogy.