I would love it if the regular expressions in several nodes also supported capturing groups & back references, this would enable powerful operations.
The use case is that quite often I have to do a bit complicated rename operations and need a whole string of Rename CHOPs to get to my goal - this feature would make that easier and a bit faster.
Prime candidates for this feature would be the Rename Chop and the Substitute DAT, maybe there are other nodes as well.
Here an example how it could work for the Rename Chop:
With () parentheses you can mark multiple capturing groups. With a numbered dollarsign you reference those groups.