I don't use my phone for anything more than calls and messages. 
I searched for 'best smartphone for bloggers'. It showed too results but none of them had anything useful in them. 
I would like to have features wherein we can use pics taken from our phone directly into the blog without having to mail or transfer.
I think it depends more on the app than the smartphone. You can sync your phone's photos with Picasa Web Albums. Pictures from your picasa account can be used directly on your blog. ( In fact, all images that you add in your blogger posts are stored in picasa ) Search for it and you will get many options.
I would also like a function which helps me upload my blog posts straight on social media without having to do it separately. Any ideas?
This feature is nothing related to the smartphone. There are apps which keep an eye of your blog feed and when you post a new article, they automatically post it to twitter and facebook. Again, search ( 1 2 ) for it and you will find many options.
I gave you the links to Google search instead of suggesting some apps as I never used any such apps. 