I started using CasparCG a few weeks ago. Without prior knowledge of Flash / Actionscript, I choose HTML as the solution to create my template. Better people than me can probably create those templates with a text editor, I choose to search a WYSIWYG software.
There is a lot of softwares available for that. For some tools have been published to make your template communicate with CasparCG.
Adobe Edge Animate
Adobe Edge Animate is no longer being developed by Adobe but because of the library written for it, it is still a good solution at the moment.
Adobe Edge Animate CC 2015 is still available to download with a CC subscription.
In the previous forum, an user shared a library he created to make template created with Adobe Edge Animate CC 2015 be manipulated by CasparCG.
He posted two videos on Youtube showing how to use that library:
The first video that show some basic functionalities:
The second video showing more advanced functionalities with a later version of the library :
A link to download the last version of the library is available in the description of both videos. At the moment I am not certain of the type of licence under which that library is available. I will try to contact the creator to see if i will accepted to release his library under a licence that would allow us to expand on it (i know i made modifications to some of the functionality I would share with other if copyright allows it).
I hope other will accept to share their work on templates created with other WYSIWYG HTML software (Google Web Designer or Adobe Animate)