Easy enough to trade for cards. I have no intention of getting a third TIE Advanced so traded off the third set of upgrades I'd never use from the Raider, which I actually use more than the Advanced models. I've also picked up the epic cruiser upgrades from the Gozanti which I haven't bought since the design didn't really catch me right away.I agree, I'm not a fan of the Epic play for X-Wing. Also, I personally don't like how the company packages small ship upgrades with them; to entice folks to buy into it in order to get it.
As a non scum person the autothrusters in the Star Viper bother me more, but eh... You know what you get and I don't need the cards unless I'm playing tournament... And then I borrow what I need if required.
Each person has their own opinion. I personally wouldn't buy into any Epic ships if they didn't have card upgrades. Also, its hard to get some upgrades since they are only packaged into $59.95+ Epic ships. E-Bay is an option. However, the prices are pretty inflated for a few upgrade cards because of the availability of them being in Epic ships only.

