It's not so much how you do things (that's mostly the same albeit the interface is a bit different) but how you present things, and the issue is that you have no control on how your stream is seen by others - now, it's just a Tumblr-style jumble of images.
The older style allowed some control over how one presented one's stream to others.
I have a friend and contact on Flickr - a very good professional artist, with a bagful of degrees and whatnot in fine art and education - who has over 25000 images there; they are carefully curated and gathered in sets and collections, and her photostream arranged so that it appears exactly as she wants to be seen.
Well ... not any more; now it's just a photomontage like everyone else's, and destroys several years careful work.
now I quite understand about the need to innovate, to refresh and redesign, and that the world is changing and FLickr needs to attract and keep people who are using swipe&touch devices more and more, and that most people just dump their snaps up on Flickr and don't carefully curate them, and so on and so forth, and that I will adapt or move elsewhere ... but to remove choice with no way to revert is rarely a good thing, let alone doing so to the user base without the smallest warning ...
I don't doubt Flickr will just ignore the fuss such as it is (there are about 8000 complaints in the feedback thread, but that must constitute a tiny percentage of their users) ...