I don't mind the looks but I find it hard to debug and have a poor instinct for "does this need a curly bracket or a parens?" That's my real issue with PowerShell, I find it very hard to predict what will work unless I know exactly what the rule is.
Shell has similar issues but I've put 20 years into it so the knowledge is there. Every time the PowerShell people describe PowerShell I think "that sounds awesome" but the ergonomics don't work for me.
Parentheses are for grouping. Curly brackets are for creating a new script block. If you would have wanted to write "function foo() {}" in another language, go for curly brackets. It's really not that complex.
Blocks always use braces. Expressions use parentheses for grouping sub-expressions. It's the same as many C-like languages. I can't imagine any situation where you would be confused which one you need to use.
Because it's an arbitrary piece of code that needs to be re-evaluated for every input item, like an inline function / lambda in other languages, not an expression that is evaluated once when the commandline is instantiated.
Blocks always use braces, but sometimes you are passing parameters and other times you are passing a block.
If I spent all day as a PowerShell dev I'm sure I would know it, but for something I reach for once or twice a year intuitiveness is a feature I would like to have.
I'd say that $_ is really weird and looks horrible. Also having to do (10 * 1024 * 1024) instead of just writing 10MB is a downgrade even compared to POSIX-compliant sh. In my other comment I've added a few examples in sh, zsh, and a better PowerShell example:
