We should be able to upgrade an "adventuring fellow" to be the best trust (or comparable to the best) in the game, the selected class should be the best healer, the best tank and the best damage class above all other trust options.

I don't get why they don't do this, make it a lot of work for the player so it's a time sink, could even allow us to trade expensive items to them to wear from a list of options.

They know this is popular (as shown by the massive queues when they added them years ago) so make them relevant again.