I do not think that Trade Route is a bad card. I just find it hard to imagine a LIKELY (of course anybody can come up with an extreme deck whioch contains ample of Victory cards) concrete deck with Trade Route and Forager in which anybody would buy the former instead of the latter.
So if there are two official cards which are very similar and one is virtually always inferior to the other I do not think that there would be a practical problem (unless one plays, like EHalcyon said, with a lot of cards from one set) with "discard a Card, +2 Cards, +1 Action" at 4$ or "+2 Cards, +1 Action, discard a Card" at 5.
Obviously it would still violate a fairly obvious design principle but my point is that there are ample of official cards which are weak/strong at their price.
-
Granary - Action
+1 Action
Set aside a card from your hand.
OR
Gain for each differently named set aside card. Discard all set aside cards.I named and changed Granary. The easiest way would have been to get rid of the bonus but I want it to remain for thematic reasons. I also like Intrigue and cards which give you options.
Now instead of being a bit too strong as before the card might be a bit too weak ... but then again the bonus is probably stronger than Harvest (you use the second option late in the game you you have already set aside Coppers, Estates and Provinces plus curses or another Victory card: so we have a rough average of 4, respectively in Shelter games 6).