We are in much larger supply of keywords than we are in supply of braces. There are 17576 unique 3-letter identifiers using the latin alphabet. We only have four symbols we can use as braces: [({<

Optimizing for minimal usage of keywords seems like the entirely wrong thing to do. It seems far more sensible to keep the usage of braces to an absolute minimum.

Yeah I don't think Pascal looks great, but that is hardly due to begin and end IMHO. Algol, Ada, Matlab, Julia and many others part of that tradition look just fine.

Not sure you are joiking about boldface, but if you are serious I think that is a bad choice. There is a real value in using plain text for code. Syntax highlighting can make identifiers bold anyway. You should not assign syntatic meaning to visual style.

Python's use of significant whitespace is a terrible idea IMHO, as I have written about recently. Leave formatting to your IDE, editor or other tools.

You kind of made my case against curlies. They look too much like parens, so why not use keywords instead which are much more clearly identifiable.

You are selectively jumping between caring about subjective aestetics and functionally reasonable choices. Begin-end blocks are great from a functional standpoint. You may disagree with the aesthetics but it seems odd to selectively decide when aesthetics and function matters.