1. Add an option to be able to turn on "View HTML" by default in tickets.
2. Add an option for which HTML element types to KEEP in the document, as a comma-delimited string (all other elements would be removed).  My suggestion is the following elements will be allowed: "p,div,h1,h2,h3,h4,h5,h6,br,blockquote,hr,pre,table,thead,tbody,tfoot,tr,th,td,ul,ol,li,dl,dt,dd,b,i,u,strong,em,abbr,cite,code,del,dfn,ins,kbd,q,s,samp,sub,sup,var".  These are all structural or built-in font styles, so they are all considered safe.  Allowing things like a head section or styles (as well as obvious things like scripts or objects) is unsafe, because they can allow injection of something that an agent will see in their browser.  Even an image is "unsafe" because it can be inserted by a user as a beacon.
3. Add an option for which HTML attributes to KEEP in each element.  Every other attribute would be dropped.  This can either be a stand-alone option, or can actually be combined with option #2 above.  It might be useful to combine with option #2, because that would allow granular control over which attributes are allowed within each element.  You can see an example of this when configuring a TinyMCE editor control using the valid_elements option: https://www.tiny.cloud/docs/configure/content-filtering/#valid_elements.
4. Add an option for custom styles to apply to the tickets' HTML.  Some might think this is redundant because you can add custom CSS to each brand, but it would actually be useful to be able to apply different CSS styles to each ticket template, knowing that each template might have different HTML associated with it.

Hello Michael,  

Thank you for the inquiry about modifying the default view in SmarterTrack. Plain Text has been the default after having tested HTML in earlier versions. As you know, conversations are many many messages and HTML elongates the conversations dramatically and slows down the browser. Based on this, we were asked to show as much information in a conversation as we can in the fastest way possible while making it simple to view the HTML for a specific message within the conversation.