Thanks for raising this. As someone who is only modestly familiar with Postgres internals or even C, but would still like to contribute through review, I find the current process of finding a suitable patch both tedious and daunting. The Reviewing a Patch article on the wiki [0] says reviews like mine are still welcome, but it's hard to get started. I'd love to see this be more approachable.
I totally agreed with Maciek. Its really hard for even an experience developer to become a PG contributor or be able to contribute effectively.