While just because a company wants this, I doubt this is the future, however...

Just a couple days ago I was thinking about this (and in fact, started exploring icon packs for my desktop) that all the UIs I use are reduced to "black and white" icons and widgets. Colors are missing, sophisticated shapes too. Sometimes I am actually wondering what an icon is meant to represent.

At my new gig I have to use web Outlook (not allowed to use my finger-memorized mutt setup), and I must say it's a pleasure to look at the UI. Still line drawing icons, but and elegant play with colors at least. Similar to how some LibreOffice Icon packs look like.

I rather hope this is the future. Use colors as accents, leverage a "grouping" functionality with them.