I'd say Vale's thesis is "Rust level performance without the pain." By making our borrow checker a lot more flexible with shared mutability, we're able to lower the learning curve and architectural restrictions significantly. This could make it a better solution for servers and games, and opens the doors to things like GUI and apps, where Rust could never really fit well.
Though, it's a lot more than that, Vale's also doing some pretty crazy things with concurrency [0], determinism, higher raii [1], and region isolation, all of which will help with preventing and detecting bugs.
What is Vale's thesis?