I dislike the templating pseudo language of Svelte (and many view frameworks). Maybe I am spoiled by react but I never ever want to write my view logic in anything else than JS. This is my main blocker for Svelte.
The templating in Svelte and Vue is (almost) html with some magic sprinkled here and there, so much closer to the end result. Using JS for everything is moving further away from the metal.
What is it about writing views the React way that appeals to you more?
You can't ship until it looks good, and the longer features are in-flight the worse management feels about the team's abilities.
You don't want situations where senior staff have to intervene on what should be a straightforward issue. It gums up the works.
JSX is JS thus it's powerful. I prefer to use JS to "sprinkel the magic", rather than using yet another (awkward) template language. Using JS for everything is keeping my mental consistent. I enjoy getting full editor support for the entire app (typing (via TS), warnings, auto-suggestions, etc...). Overall it feels more consistent, more composable and more functional (as in Functional Programming) to me.
IMO a just a simple function/array based templates work better like this that I have used recently:
div({class: 'test'}, b({}, 'Hello world!'))
Or for the array syntax:
['div', {class: 'test'}, ['b', {}, 'Hello world!']]