File attachment:
Both in desktop and web-mail, drag and drop is nice but selecting multiple files in the attachment dialog is a must for most users. daily tasks are severely taxed by this.

Addressbook:
Having lots of addresses and no easy way to sort them in the order you want is also bad for productivity. User ask for the possibility to sort by first/last-name or by company. Have address as list or card. ovarall choices.

And stuff they find in outlook like favorites and search folders are also asked for