It could have been nice to see the Rust rewrites finished instead of shelved due to costs. AI is very expensive so if they have the money for this, they could've probably started that up again. Firefox is generally good feature wise but Google gets to almost usurp the W3C because pretty much every other browser is using the Chromium codebase over Mozilla's.
It was sold as supporting a much more concurrent rendering engine, which they felt was basically too hard to write correctly/safely in C++, but presumably would be considerably faster.
My interest in a rust web engine is absolutely memory safety, because it's a fun game at work to post the "RCE o' the week" seemingly caused from exposing literally millions of lines of C++ to the wild Internet https://chromereleases.googleblog.com/search/label/Stable%20...
