Reasons to reject "if/else and switch as expressions" looks very naive. Can't believe it's coming from Chris Lattner. A lot of languages like Python, Haskell and Rust got this right.
If I were to catch an exception, I rather catch it at a line level in a block.
If you read through https://mail.python.org/pipermail/python-ideas/2015-Septembe... (a freakin long debate) you will see that sometimes simplifying things can hurt, although in this very debate if/else expression is favor over the proposed new syntax in that PEP, which I am against.
Some languages restrict where block expressions can be placed, but that's not a meaningful difference between if expressions and ternaries, that's a difference how blocks are treated. More concretely: I know of no language that allows "if expressions" that aren't just ternaries (i.e. either the language allows blocks as expressions or it doesn't, but given that choice, no language then further distinguishes between if expressions and ternaries).