I share some of your disappointment in the current state of the media up-loader. I've always believed that form needs to follow function, not the other way around. I don't need "pretty" if it adds unnecessary steps to my workflow, and that's pretty much how I feel about media management in 3.5.
That being said, under the 'Insert Meda' dialog, you may or may not have noticed the drop-down where you can filter uploaded items by 'Uploaded to this post'.
If you intend to use several images to create a gallery, first click on your images individually to edit the attachment details from the column on the right side of the editor. Then on the far left, select 'Create Gallery'. Once you do that, you will notice that you have to return to the drop-down filter and select 'Uploaded to this post', again, before you can effectively use the 'Create a new gallery' button in the far right lower corner. Even then, you may have to backtrack if your multiple images don't pop up in the editor for gallery insertion on the first try.
So, yeah. (IMO) There's a minor (re)learning curve involved, and some workflow inconvenience issues. As far as I'm concerned, it's a lesson in why "wow, that's really cool", needs to take a back seat to functionality and workflow considerations. But, that's just my opinion. It still works.