I can give you some answers, right now there's a lot of improvements and changes happening behind the scenes.
3 - that's been actively discussed over at the dev channel, I think the overarching goal will be to make a more indepth search with filtering. I definitely think a 'context ' drop-down would be great here, show me just users, magazines or articles that march xyz
4 - that sounds like a good candidate for a user setting, being able to choose from top, hot, newest or active, having another top like that just shows your subscriptions might be handy too.