Many WordPress.com users don’t know their sites are guinea pig sites that new WordPress software upgrades are tested on. The upgrades are done by Staff and introduced about a month before the developers fix the breakage and tweak the code and make the upgrade available to WordPress.org users for their self hosted sites.
All the new improvements we’re introducing today are part of the WordPress 3.9 release, which WordPress.com users test out first. These and other updates will be coming to all self-hosted WordPress sites in April. Meanwhile, you can already help test the second beta. From: Introducing Smoother Editing and New Playlists
If you are noticing issues cropping up then see here please Changes to the Visual Editor, including Images and Paste from Word
I’ve been at WordPress.com for 8 years and I no longer sweat this stuff. I choose to simply wait it out and when the dust settles I learn which new hoops we have to jump through to accomplish what we were able to do before.
I no longer post into support forums threads reporting issues due to the changes and sharing what the “contributors” uncover because life is too short to spend it skipping rope in time with someone else calling the tune. I just remain calm and carry on by clicking into the next support forum thread where I can help someone.