I agree with most of these, but I can't really get behind floating windows. Android is a mobile OS at heart; the largest devices it will typically be used on are tablet computers. Multitasking with floating windows will just turn Android into another desktop OS, and make everything messy. Consider the screenshot in your article... Does anyone actually want to watch a tiny YouTube video in the corner of their screen while they browse the play store? First off, humans are only really good at focusing on one task at a time, and secondly, the video is blocking a lot of the controls and content of the app below it. Sure, you could reposition it as needed to get to the content it's hiding, but come on. It seems like a hacked-together attempt at turning Android into Windows. Also, why in the world would you have "HD" enabled on a video that tiny? That's a waste of bandwidth.
I agree that HD video on my Galaxy Nexus is a waste of bandwidth but if you have a Nexus 10 it maybe make sense. You have plenty of space. :) Anyway I'm thinking more app like reply to text message or chat like whatsapp and similar. Floating windows are more for quick actions and I'm not thinking to change Android into a Windows like OS. It's not a sensible UI for a touch screen OS with limited screen size and unprecise fingers! :D
Like the SMS app's "Quickmessage" pop-up (which I'm not sure is even a stock AOSP feature), I think temporary floating windows for chat-like apps are appropriate in some cases. Like, if you get a text message, it can pop up in front of the activity you're currently using. The difference is that, like with Quickmessage, you can't interact with the activity behind the pop-up without closing the dialog first. It's essentially its own activity, with a transparent background showing the other app you had running. I don't think this departs too much from the mobile-centric design I was talking about, but an app that is constantly floating over all other apps certainly does. Perhaps it's more appropriate on a tablet, as you said.
Yes but there is a smart idea that solve this problem. Have you tried Ninja SMS? It let you reply to a text message in a floating window but it let you collapse the window to a little circle like Facebook Messenger and you can interact with the current app without big trouble! :) I think the good is in the middle like in every thing. We don't want a Windows like OS but we'd like something that get the best of it! :)
I can see the appeal of that, but I don't prefer it on my own device. I tried using the PA Halo feature for a while (on Carbon Rom), but it felt like a gimmicky replacement for my already-existing notification panel. I like the notification panel. It shows you new notifications, it's there when you want it, and when you don't, it's not taking up any screen real estate at all. Halo is always there (at least a little bit), it shows me the same thing as the notification panel does (while being more difficult to clear notifications from/view their originating app), and it really adds no extra functionality other than allowing you to float one app over another (although it takes up most of the screen and there's not much advantage over simply switching to that app).
I tried a bit few floating apps and I really like them. Anyway it's depends on personal taste! :)