Currently, the requiredAttendees methods setAsync and getAsync have serious issues when resources of room type are used. I will add below my review of the three methods exposed on requiredAttendees object (picture in the link):

http://s17.postimg.org/satnvyrz3/Required_Attendees_Calls_Behavior.png

Need a Change Tracking API in Word.

It seems that Outlook REST APIs is providing new scopes and the possibility to request the shared mailboxes. See this question on StackOverflow http://stackoverflow.com/questions/38616499/what-is-the-purpose-of-the-new-read-user-and-shared-mail-delegated-scope-in-az/38626322?noredirect=1#comment64649553_38626322

The problem now lies in the fact that we cannot "discover" the shared mailbox for the end user. It means that you cannot create an application that show all the shared mailboxes for an end-user because we do not know the name/id for them.

I'm sending email on behalf of logged-in user in my app.
I would like to ability to include email signature defined in the user's mail settings.

Currently, there is no ability to hide or show the task pane from the Office Javascript API.

VBA COM Object model supports Application.CompareDocuments to compare and merge word documents. Office.js lacks this capability. Please support this through Office.js

It would be very useful if add-ins dropdown menu could contain dynamically generated items. Now the displayed content in the ribbon dropdown need to be hardcoded even for sub-menus which limit the capabilities of add-ins commands.
See question on stackoverflow
http://stackoverflow.com/questions/36315571/dynamic-content-in-add-in-command-with-ribbon-dropdown-menu

Right now the Graph SDK upload limit is 4MB (http://graph.microsoft.io/en-us/docs/api-reference/v1.0/api/item_uploadcontent). It should be at least 100mb, such as OneDrive SDK provides (https://dev.onedrive.com/items/upload_put.htm)

Currently an add-in command will disable if multiple Outlook mail items are selected. It would be really useful to be able run certain commands by iterating over a collection of the selected items.

As referred to the post:
https://social.msdn.microsoft.com/Forums/office/en-US/720a1bd6-abb9-4f75-863f-1fc33256a629/is-there-an-event-for-when-recipients-change-in-outlook-2013?forum=appsforoffice

there is no event JavaScript API an add-in for Outlook could use to react to a change in email message being written (compose mode).
For example if the user adds further To, Cc or Bcc Addresses, it would be advantageous if the add-in could react to it and display relevant data.

If I have my base SharePoint url, and I have admin credential, Still I can't fetch all the sites/site collections detail through REST API. Need a REST API, which gives detail about detail about all the site collections.

While reviewing the O365 Preview API I was wondering what about Task-Management. Currently there are two systems for task management (Exchange and SharePoint). Would be great to see a roadmap for TaskManagement in the O365 Story and of course get an API to easily connect Apps to consume tasks. (No CSOM required just give us REST :D)

When I'm creating an App on Office 365, users can pin them and select them from the "My Apps" menu in the new Office 365 ribbon.

I would like to recreate this menu/whole ribbon in my app (desktop or web, whatever), to bring a consistent experience to my end users. By this, my users could easly switch between O365 Apps and my app.

I'm inspired by TechEd Europe and all the O365 sessions. This is what imho is missing and is very important atm.

Something like:
dev.office.com/me/apps/pinned

Following this StackOverflow post, I suggest this feature.
Allow filter and order for SharePoint lists queries through Microsoft Graph API.

We would like to have the graph call for joined Teams to support the favorite status, like in the Teams app.

The isFavorite property of the /beta/me/joinedGroups endpoint does not return the same favorite-state as reflected in the Teams Application.

{
"id": "138944aa-3d78-4f70-9a67-d34c3afe0ee4",
"accessType": "public",
"displayName": "a team",
"EmailAddress": "ateam@.....onmicrosoft.com",
"isFavorite": false,
"LastVisitedDateTime": "2018-03-22T10:24:20Z"
}
There currently is no way to get the 'favorite' state a team has in the teams application.

Only a post request to /groups/138944aa-3d78-4f70-9a67-d34c3afe0ee4/removeFavorite seems to influence the isFavorite property. But this doesn't change anything in the teams application

This affects all resources that support extensions but let’s take the User resource as an example:

Extending the User resource currently requires an entire User Profile read/write consent (User.ReadWrite).
We only want to read and write additional data that we provide to the User resource and not modify the entire resource. Users might be hesitant about consenting to Apps that could potentially corrupt their entire user profile.

Our organisation creates hundreds of sites for each project or client.

We rely on security to figure out who can do what. It would be nice to be able to get the list of sites available for a given account globally.

/sites returns an errors
/sites?search= returns stuff, but seems not be in the beta endpoinnt anymore