I’ve been speaking to app & website developers about BrowserID
and Apps for a few weeks, and the feedback has been great —
webdevs & entrepreneurs are very aware of the dangers of relying
on Facebook, Google, or Apple as the bridges to distribution or users.
What we need from you, Mozilla, is not "a better way to sign in", or better support for whatever your vision of a web app store is. We need Web Intents (http://webintents.org/), or your iteration of it. We need you to create a kick-ass UI for this. We need you to help take back the web before it succumbs to mega corporations entirely. Please, Mozilla, have the foresight to recognize what's really at stake here.
To be more concrete: When a web page uses an intent like "upload a photo", Firefox will check to see if any of your "apps" support that intent. For example, if Flickr has an OWA app and you have already installed it, then Firefox will instantly ask if you want to choose one of your Flickr photos to upload. If you click an intent that the browser doesn't already have a handler for, it can offer to install an app from the web to handle the intent.
Open Web Apps is part of the infrastructure to turn Web Intents from a low-level API into a complete user experience. And BrowserID is also part of that integrated experience. (In the full vision for BrowserID where the browser manages your identities, you can do things like install an app and be "logged in" instantly without creating an account or typing a password.)
If this happens as part of a large integrated experience as you promised that's fine, but I fear that you are taking on too much, going for a complex and over-engineered package that may never be ready or actually usable, instead of concentrating on this one single important thing which really needs to get done.
Similarly, the apps project is a lot about recognizing what mobile apps did well, and filling in the gaps in the web (stores, receipts, APIs) that will make it possible for people to translate their mobile appdev skills into the broader web.
browserid & apps & intents-or-something-like-it are all mutually reinforcing, IMO.