As someone who has spent a _lot_ of time writing declarative and procedural macros, the important thing to ask before digging into a macro is whether you need a procedural macro at all.

Complex proc macros absolutely do slow builds down. In many cases, a proc macro only need to be a stub that can delegate to a declarative macro.

You may not need to use syn/quote, but if you are doing any sort of processing/parsing of Rust code you pretty much need to.

FWIW, I really hope that the Rust project focused on finer-grained token matching in declarative macros so we can migrate most proc_macro code away. The macro system is powerful, but nowhere near where it needs to be.