And all that upgradable cards don't look cool with Swindler around
Why?
I mean, sure, you'd almost always prefer not to get a card swindled. But why would it be particularly bad for the Travellers?
We know from the preview that Page costs $2 and Hero costs $5. So the other three ones are probably $3, $4 and $6. I would assume these prices are supposed to roughly reflect not only the strength of their one-time effect, but also the potential of exchanging them. (Or aren't they, Donald?)
So sure, getting your Page swindled into an Estate early hurts a lot. But that's the same as with (almost) any other $2 card. Getting f. e. a Silver for a $3 Treasure Hunter doesn't sound particularly bad. And with the $5 Hero, it will depend on how early they are hit just as with most of the $5 cards - swindling them early hurts a lot, but later on Duchies are not so bad and most other $5 cards usually aren't, either.