Contact Category COLOR should match its selected Category Color.
The color of the Contact Bubbles (circles) displayed in the People list in Outook for Mac 2016 (365), should match the color of the category set for those individual contacts. WHY in the world would Microsoft engineers assign random rainbow colors, that have zero purpose or relation to the contact's identity, when those contacts already have a color (of importance) tied to their selected category?! Just Reference (or use) Microsoft Outlook for Mac 2011 for an hour to understand how and why that contact category color is so important and useful (for inboxes, contact lists and calendars). At the very least just set those contact bubbles to an single color that doesn't conflict with their actual contact color.
David Weale commented
The ridiculous aspect of this is that a list of contacts can be sorted by category. This can be verified by displaying a contact's details, in which the contact's category and category colour is displayed in the top right corner of the details window. This however is not otherwise visible, leaving the user with a categorically undifferentiated list of contacts, sporting random-coloured discs displaying the contact's initials; but to what purpose?
One of the biggest failures with Microsoft Office 365 is the loss of Category Color throughout the Outlook Interface. From incoming emails, to address book contact colors, it's absolutely insane that established Contact Categories are no longer applied to the Contacts & Emails in Outlook. And as noted, it's not only they the category colors are not applied but completely random colors with no meaning are used instead.
We used to see the category color assigned to the full subject when sitting in your inbox, now there is a small, very small, colored box only to the right of the subject line. This makes it much mire difficult to distinguish the category of the email.
I couldn't agree more! It's the same problem (and request) with Category Color on incoming emails (see link below). WHY is Category Color no longer applied? Microsoft needs to fix this ASAP!! https://outlook.uservoice.com/forums/293343-outlook-for-mac/suggestions/9083365