Hmm, I see your points on Barterer. If I raise the cost to $2 it seems to balance it a lot better, otherwise it's too good at the moment.
View needs at least to be every 4 treasure cards, otherwise it is strictly superior to estate at the start of the game, something no other alt-VP that can be improved is. I think 5 is a good benchmark thus far, after a bit of testing. It is still broken with trader in most kingdoms, particularly with +buy, and it works really well with horn of plenty and cache as well.
I do still think there's room in the $0 region for the no-treasure restriction, but maybe something a bit less powerful. Such as the following.
Messenger
$0- Action
At the end of your clean up phase this turn, draw seven cards instead of five.
You may not buy this if you have any treasure cards in play.
With the specific wording so it is vulnerable to handsize attacks, and can't be stacked.
I've been tossing around the idea of doing a set of these, but the catch is then the "a useless rock" problem is more likely to enter play with more cards that have a no treasure restriction, so it might not be a good idea.
I don't know how I managed to make my cantrip-curser that can't be spammed having the name "Victory", it was supposed to be called "Traitor". Maybe that's why there weren't any comments about that?