That's quite some work you've invested here. I've looked at them from two perspectives:

• How does it help when I'm writing code?
• How does it help when I'm reading code (mostly written by someone else)?

In summary, your suggestions don't perform that great. These are rather nerdy ideas where I don't see which problem they solve. There isn't much to be added to the comments of other monks, so I'll keep attention to two items:

I challenge the claim that closing more than one block with one brace allows search for missing closing bracket to be more efficient. It just hides problems when you lost control over your block structure. Source code editors easily allow to jump from opening to closing brace, or to highlight matching braces, but they are extremely unlikely to support such constructs.

I challenge the claim that extracting of substring is a very frequent operation. It is not in the Perl repositories I've cloned. Many of them don't have a single occurrence of substring. Please support that claim with actual data.