I think AW will never be compatible to Android. Only work with iOS is advantage not disadvantage for Apple revenue and stay as luxury brand point of view. Apple has no intention to have 100% smart watch market, in fact, for any luxury brand item, which Apple products are, most of them do NOT want to own 100% of market, because it means they will have to satisfy both high-end and value-focus customer. With few exception, lots if not most of Android phone customer look for value added. More feature for the $$ pay. Value-focus is more important than being the top of the quality on build, look, and feel. Just as same as Rolex will never interested on selling new watch less than $1000 or get 100% mechanical watch market, or Porsche will never be interested on selling new sports car less than $20,000 or get 100% sports car market.
Yes...I would actually be pretty shocked if Apple took any steps towards making an Apple Watch talk to an Android phone, but some tech blogger (can't remember which one at the moment) was speculating just that recently. I don't see it happening either, and I don't see them going to great lengths to accommodate other watch makers directly. Apple has never tried to be everything to everyone. They know there is a market for the products they make and the way they like to make them.
Edited: With regarding battery life, AW last 1-2 days full function, same or more than all iPhone released, and 72 hrs extra when running low and switch to power reserve mode. AW is accessory (definition of accessory: something added to something else to make it more useful, attractive, or effective) for iPhone, not as stand along smart watch. Apple never sell it as stand along device. Most of us charge our iPhone nightly, unless forgot same as we will forgot to charge iPhone, why does an accessory of iPhone need to have longer full function battery life than the master device? It is not a direct mechanical watch replacement. It is a smart watch could do 1000 more things than mechanical watch, and happen to be able to tell time also so one does not have too wear mechanical watch. If one feel the need to have a device to tell time without have to charge daily, one could always wear both, one wrist with AW and another wrist with mechanical watch.
Yup...for how I use it the Apple Watch is a fantastic accessory to my iPhone, and I have yet to run out of battery. It's always between 10% and 40% when I go to bed, and I just charge both my iPhone and my watch. No issue at all. Personally I don't understand the issue with nightly charging, because for me that routine is easier and more foolproof than remembering to charge a device I only need to charge every few days or only a few times a month. I also have little problem reading the AW in bright sun, but I will sometimes switch to a face that is big and bold when I'm out in the sun (like X-Large). But of course some people just can't stand the fact that the battery won't last a week, or that the watch face isn't always on, or that the watch can't do everything without the iPhone close by. None of this bothers me, and I see the watch face turning off as being good for privacy anyway. Oh well... they will have their options and that's fine. As interesting as some of the other smartwatches are, their features and capabilities are too limited for my needs.
Sean