A couple of ideas:
The ability to rename sends so you can see where they’re going, rather than seeing send 1, send 2, etc. Or perhaps the send can be automatically named for the destination.
Recursive scanning of the VST plugins dir so that users can organise their plugins or leave bundle dirs intact.
Two things, one the first part is already done, right click on the send and hit ‘Rename’ 
In as far as naming it for where it is going, there are other issues on that, especially when dealing with external jack programs.
In as far as feature requests in general, they need to be put in Mantis, click on the issue tracker link up top to get there and create yourself an account to submit a new issue.
Seablade
The edit button is missing, so let me remove item #1 - just found it! D’oh!
EDIT:
Seablade, ran back here to try to correct myself, but you beat me to it.
I may just go and create a Mantis account. I’m really digging Ardour, now that I’m doing my first serious project on it. It’s only a re-master so I can make sure it has what I need, but so far, so good. Kudos to Paul!