Cinnamon Writer seems to be a really good choice.
I sent the author an email to ask about its development and donation.

EDIT:

I definitely want Cinnamon writer as word processor!
I sent an email to Claus Desler and he kindly answered to me. Here the email text he wrote:

Thank you for your interest! The next version of CW is in alpha phase
right now, and my hope is that I can progress to beta stage within a
couple of months. Development is primarily on AOS4, but cross-compiling
to Morphos will not take more than a couple of days. When I reach a
decent beta stage of the program I will compile a morphos version and ask
morphos users to help with beta testing. I have attached a screenshot of
CW. This version is already quite dated :) Don't worry about donations
before you actually got the new version of CW running on your computer
Best regards
Claus

and this is the screenshot:
http://s4.postimg.org/hon78diyl/Cinnamon_Writer.jpg

A little more patience.