Lattner is a smart guy, but I think Mojo might be the wrong direction.

Time will tell.

History has not so far been kind to projects which attempt to supplant cPython, whether they are other Python variants such as PyPy, or other languages such as julia.

Python has a lot of detractors, but (despite some huge missteps with the 2-3 transition) the core team keeps churning out stuff that people want to use.

Mojo is being positioned "as a member of the Python family" but, like Pyrex/Cython, it has special syntax, and even worse, the calling convention is both different than Python, and depends on the type of variable being passed. And the introspection is completely missing.