Yeah, I used 1. in a large media company, it was my bad because enterprise CMS’es are complex and there are lot of workflows. Isolation of frontend and backend works best for it and you have the headache of having to deal with legacy frontend code as well.
LiveSvelte by itself looks really cool and I would probably try it in my next project. The only issue in my case is frontend code changes need backend changes as well, this maybe a unique problem to me because I have frontend only devs in my team to whom I would need to provide access to backend source code access as well, otherwise I become the bottle neck. It is more of an organisational hierarchy thing than the code itself.
Also, a lot seems to have changed since the last time I looked into LiveSvelte, looks a bit mature now. Either way, let’s see where this goes. Please do update us of your journey if you chose to work with LiveSvelte! 
