While a good discussion is always fun, I think good to point out that this will never actually happen: PSA: Julia is not at that stage of development anymore
There will be a time when we start working on Julia 2.0, which will include some breaking changes, or we wouldn’t call it 2.0, we would just call it Julia 1.x for some value of x. At that point in time, we can consider breaking changes. But despite what it sounds like, this is not the time to make all the random changes that anyone might want to. Frankly, that time has passed for Julia and will never come again. There will probably be a few renamings of unfortunately named things. But that’s not what the 2.0 release is really about.
Your proposed changes would create such massive havoc throughout the ecosystem that probably more than 90% of code will stop working. There might not be any major packages left standing, and the reputation of the language would be devastated.
Removing && and || is basically impossible. The best you could do is introduce a more attractive alternative, and hope that it wins out over time. But so far I haven’t seen any alternatives I would use.