Quote From Juc:
I also see that it should be an integrated whole and should be coherent, but I don't see why all the above adds up to argument being essential. It seems to me that it can be artificial to have to find something to argue about.
I wonder if part of the problem is the definition of 'argument'. I don't think it necessarily implies taking issue with other people's work in a contentious sort of way (although, of course, if the topic fits the originality criterion and is worth spending four years on, surely there will be some scope for pointing out gaps / modifying previous scholarship).
When people say argument is essential, they generally just mean it's a good idea to have something to say and to be able to say it within a logical structure...If the answers to 'so what? is there a point? what does all the detail add up to?' are missing, then it's unlikely that you've produced a terribly integrated or coherent whole, either.
But if you're writing proposals, certainly don't agonize too much about the content of the conclusions. You just have to be sure there are worthwhile questions to be answered & show that you won't be reinventing the wheel. In the case of specific topics, if you're not sure whether an idea is MA or PhD material, that's what supervisors / potential supervisors / advisors in your field are for.