Agree that its a really big deal. Mobile support is huge.
We actually built the inboxsdk that you are referring to. There are a ton of extensions built using it and >10M end users using apps built with it. We've worked really hard to make sure apps built with the SDK are compatible. If you have any examples of 2 extensions not playing nice, def let me know.
Looking at it now, it's actually mostly InboxSDK extensions that are conflicting with Gmelius and some other custom extensions.
Having 10+ extensions all trying to modify the DOM of one site at the same time is bound to give some problems :).
Curious to see if Streak will switch to this new official way, although it seems that a lot of the stuff you're doing won't be available to Add-ons.
Gmelius is actually using parts of the SDK. But they are really aggressive and do some DOM manipulation. In general we hope that users of the InboxSDK never need to actually touch the DOM ever. The SDK handles coordination across extensions. Ofcourse extension don't have to abide by this and hence the conflicts.
As for Streak, we're planning on a mixed approach. The add-ons from Google support very few UI entry points (at least for now). Streak's entire UI only lives in Gmail so we need a lot more integrations. We'll use the Google sanctioned way when possible and fall back on the extension as we currently have now for the other cases.
First of all, big shoutout to InboxSDK / Streak folks. Our extension, Fyle (http://www.fyle.in) would've been ridiculously more difficult without it.
We're having an issue with Gmelius interacting badly with our extension. Basically, we never enter our messageViewHandler code when Gmelius finds a tracker. Have reached out to them as well.
I also hope this will improve the privacy/permissioning story for gmail add-ons. I believe currently any extension has full access to the page meaning they could read all your emails. For some of them that's obviously required as part of the functionality but it would be great to have more fine-grained permissions for things that don't need full access.
Most successful/useful/business extensions usually request oauth access to the backend Gmail API from the user anyways so its not as big of a concern as you might think.
Looks like it will from the screenshots (https://4.bp.blogspot.com/-HeFnmVgMiJ8/WMDL3f4TQgI/AAAAAAAAB...) - each app will have it's own icon and hooks into emails/threads. I too have built a few gmail integrated apps and this will be super nice and convenient.
Having the power to do this with Google's consent _and_ have it be available on mobile devices is huge.
I hope this solves the problem of conflicting Gmail extensions, I currently just have too many installed that don't place nice together.
[1]: https://gmail-message-id-finder.co/ [2]: https://www.inboxsdk.com/