> I paste "Australian companies established in 1997" and want to just change the year.
I don't understand.. why can't you edit that ? There is no cursor in the text input to do so ?
> I have to be very precise
This is going to be a problem even with search. There are a LOT of categories, so even with search it is very likely you are going to get a lot of noise in your search results. It should be possible however to allow for at least typos, if VE would use prefix search instead of title prefix matching. I have filed a ticket for that in phab:T359302.
I've also been thinking that one of the problems with adding categories, is that you can not choose a higher or lower level categories from a match. It might be a good idea if you could navigate the tree from the Category input field.