We've had visitors from Kuwait, in fact, they were the first to come into Thailand this year we were told under the then COE. The Thailand Pass is the only way to get in.
I think it’s great they are simplifying things even more. Having worked with 15 or more of our guests over the past few months on the COE the Government system was for the most part excellent. There were a few update issues with some embassies not aware of the changes, mostly with the introduction of the Samui Sandbox. If they use the same IT system and simplify it, it will be quick and fast. Congratulations to the TAT IT team who have made it happen. 100% of the issues I saw were user errors and not the system. Have your documents in order and it will be easy.
Raf, I have filled out the COE for guests and recorded a podcast on how to do it. I agree with Tiffany, if you have all the documents start a new one but it won't be approved by tomorrow. You will not get past check-in at the Airport without it so I'm sorry but you won't be travelling tomorrow. DM me if you need help.