Two things:

1. Do NOT do anything that the JS/NodeJS ecosystem did (especially the unusable stacktraces).
2. Do NOT ever force any form of static typing onto the user. Make it at least opt-in.

Do not use Markdown/CommonMark for documentation. Use more expressive and configurable format like ASCIIDoc.

This is absolutely trend that I cannot understand. Markdown was designed for writing blogposts with almost not typesetting. Yet for some reason people thought that it will be a great format for documenting code, which need few more additional stuff, that was never a plan for MD (cross document references, math, graphs, tables, definition lists, etc.). Just stop and use ASCIIDoc for gods sake.

Well, someone asked for my opinion and I wrote my opinion.

I worked both with Golang and with Typescript. Golang is just horrible and 95% of my problems are related to the language bitching about some type specific things. It’s just annoying.
In Typescript, I mostly just type my stuff with interfaces but it also often gets in my way. External libs either miss type information or they are just wrong. D3 is especially hard to work with. Also everything that is related to DOM elements. And I cannot even check if a variable matches a certain interface, thus having to have a type property on certain interfaces.

I’ve worked with PHP for a long time and never had any type related issues. The addition of type hints was nice but it was all optional so one could use it in places where it makes sense.

I also love the way Elixir handles it with pattern matching, therefore I do not understand why everyone wants to force a strict type system onto Elixir.

Just my 2 cents. (But I guess we both had the same discussion a few times already on the Elixir forum )