Perhaps it would be better for you to just reimplement it in workbench for your purposes and maybe at some point in the future you can make a simpler PR to disable Geanys features so only yours are available, if you think having both will confuse users.
Hmmm...I think not because I do not really like to duplicate it all. Also a more dynamic solution would be useful for others too. Maybe I start a re-write some time but I got the feeling it won't have good chances to be accepted.