I'm in Yellowstone right now - I don't see any serious problems - lots of bears (and lots of rangers available to handle the traffic), Fox Den hullabaloo (big goings on there and lots of rangers available for traffic control). The only thing I notice is that Blacktail Plateau Drive is closed and it's usually opened by now - they are waiting for it to dry off and regrade from winter, and Slough Creek campground is closed (no reason). Either have no date as to when they are open.
But we are on the Northern Tier only (have been to Old Faithful only twice in the last 2 weeks), and from another who said if you don't have reservations, you're pretty much out of luck unless you want to boondock and then it's first come, first serve, and a limit for how long you can stay.
Spring has come late (as with the rest of the country), so animals are late to show up. We were in Cooke City today and it snowed. Also not as much snow fall so river, lake and pond levels down, except in around the NW area where they are up more.
If there's anything you would like to know specifically, let me know and will either find out or send on where you can find it.