My idea is that there should be developed some upvote bot for promoting posts from new users for free, for example first two months.

This is a good point of view. My thoughts on this are there are abusers everywhere who will take advantage of it. The #introduceyourself blog is most crucial in my point who needs a show of support of the community while having a picture holding Steemit Card. As time goes by, and to continuous effort of the developers we can see some better changes in the future. Hodl on and buckle up! We gonna see the moon very soon