Firstly, I'd like to clarify not all of these arguments hold water with me. I posted them because they are relevant to some people that I know, and thus may similarly be relevant to some people here, and they had not been posted yet. Similarly, I do not want to present them as full arguments in themselves, but rather as points that should be taken into consideration.
-More hung parliaments. Very few people are fans of the current conservative/lib dem coalition, yet with AV we'd see more governments like it.
1. Tell me how hung parliaments are a bad thing and we'll talk.
Hung parties are bad because, unless a coalition is formed in order to form a majority, very little gets done. I don't know anybody who likes the current coalition, and thus I conclude that, for these people, this can be counted as a bad thing about AV, as coalitions such as this would occur more frequently. Hence, for these people at least, it is an argument against AV.
-Smaller parties fare better, but all smaller parties fare better, including extreme ones like the BNP.
--This is compounded by the fact that, under FPTP, lots of people whose first choice is a smaller party don't vote for them because they don't have a chance, and instead vote for their favourite of the candidates who have a chance. Under AV, this would change.
2. The BNP are voting against this because it would hurt. Small extremist parties tend to do worse because they have to get 50% of the voters to pick them as a preference, then if they do win it's because a lot of people wanted them. If you have a problem with the BNP getting in when the majority of people support them then you have a problem with democracy not with AV.
3. Ok this a pro. Are you seriously saying this as an argument against AV? That people will be able to vote for the party they support rather than being forced to vote for someone they dislike to prevent someone they hate from getting in?
Once again, I personally don't have any problem with smaller parties getting more votes. I added this because I know quite a few people who are so rabidly against the BNP that they consider this a point against AV.
-There are very few other countries (3?) that use AV, presumeably for a reason. Furthermore, I have heard (though I in now way present this as an absolute fact about all australians) that a large number of australians, who use AV, do not like it.
4.This is a logical fallacy known as the appeal to popularity. The number of countries using the system has nothing to do with how good it is. It may be that only a few countries use it because it's bad but if that's the case then you should have lots of nice juicy reasons not to use it, but even then the reasons you come up with would be the argument against it not the fact that it isn't widely used itself. If I'm the only person in the world with a magical genie lamp that gives me three wishes and you get the chance to have one too you wouldn't turn it down because only one person has one. You might turn it down because you know that the genie inside is a trickster genie who'll twist your wishes to be bad but that's unrelated to the number of people who own one. When looking at it you should be thinking why does only one person own a genie lamp/4 countries have AV. In the genie lamp example it's because genie lamps are so incredibly rare. With AV it's because especially in a two party FPTP system switching to AV requires that the parties which lose most in the change make the change.
Not quite right. This would only be an appeal to popularity if I said "not many other countries use AV, therefore we should not". The experience of other countries with AV does not dictate what the UK's would be, but we can say that our expeience would be similar to a degree, as the two countries share lots of factors in common. It doesn't mean that we will have the same experience, but rather that we are likely to have an expereince that is not very different.
-Some people's vote will count for more than others. There will be some people who only have their first choice count, and others who have their first, second, third, etc considered.
5. Under AV everyone's vote counts for the same, it essentially works by having a series of elections without the cost of holding each individual election. At the end of each election the votes are counted up if one person got 50%+1 they win, otherwise another election is "held" immediately after with the least popular candidate eliminated. If someone voted for the unpopular candidate as their #1 then their number 2 vote is counted. Anti AV campaigners claim that this means their vote has counted twice and this is true, the thing is if you voted for a popular party who is still in the running your vote is counted again too so your vote has counted twice as well. Of course they helpfully neglect to mention that and claim that your vote has somehow counted for less because you weren't forced to change it.
I know perfectly well how AV works. It is an undeniable fact that people who have their first choice as one of the more popular parties will have their second and third choices given a lot less consideration than someone whose first choice is a less populat party. I know people who object thoroughly to this.
-As simple as our current system (say who you would most like) results in a lot of people not understanding it (there are tales of people who think you have to 'vote them off'). The new system has a lot more ways that peole can get it wrong (e.g. do you give your favourite candidate the biggest number or the lowest one).
6. Yes it's is slightly more complicated. Ranking your candidates in order of preference is harder than making a mark in a box. But on the other hand anyone with a primary school education should be capable of writing a list of numbers. It's still extremely simple so this one comes down to a matter of opinion. Do you think it's worth ballots being a tiny bit harder to fill in?
I personally would not have any problem, but I have certainly learned that there will be quite a few people who would foul it up somehow. As I said before, this is not intented to be a full argument, but rather a point to factor in when weighing up the pros and cons.
Bonus: You didn't mention cost, which is disappointing because it's one of the few valid points I've seen against AV, so I'm going to throw it out there.
I didn't mention cost, because it had already been mentioned.