Sorry but this explanation is like a lot of Microsoft "explanations".
Lazy and ambigious.
---- Office Proplus is our most popular option so we use it for shorthand. Really shorthand for what? Does everyone in the world know that?
---- "mainstream Office clients" what exactly does this phrase cover?
A grid of your products detailing the actual product name that everyone uses would be good for every level of your price plan set
Along the lines
Small Business
- Business Essential - Yes or no
- Business - Yes or No
- Business Premium - Yes or no
- Exchange Online - Yes or No
- Skype for Business Plan 1 and Plan 2
- One Drive for Busines Plan 1 and Plan 2
- etc..
- etc..
Enterprise
- Pro Plus - well obviously Yes
- E set of plans - Yes or No
Retail
OEM Desktop licenses
- 2007 - Yes or No
- 2010 - Yes or No
- 2013 - Yes or No
- 2016 - Yes or No
Third Party Clients
- Apple Mail
- Thunderbird
- Windows 10 Desktop Mail App...now there's an interesting question
- Android Phones
- IOS Phones
(something else out of the Mad Hatters tea party that is Microsoft Corporate strategy - Promote Outlook as the email client, it can have connections to every major other email provider and on-premise solutions.......except for Microsoft's own flagship mail system Exchange Online.)
Does this change also apply to Hotmail/Live as they appear to have been absorbed into the Exchange system?
Volume Licencing agreement?
Government, Non Profit and Education agreements?
Another Alice in Wonderland announcment, Non profits couldn't purchase CSP licences until a couple of months ago and had to go through the Volume Licensing route for say 5 years agreement, so now they have to go through a plan to migrate to CSP.