Defensive Training is kind of an odd card. For a cost of 2 (one card, one resource) you...tweak the contents of your deck and discard pile. You aren't making progress towards winning, you aren't preventing yourself from losing, you aren't even changing your options in hand this turn. You're essentially giving yourself the opportunity to draw a different card later, for an upfront cost of resources. You better make sure you really want that card! Also, note that it only gets Protection events back into your deck, so no Crosscounter recovery...at least not directly...

Use cases (ideally you'll fit multiple of these):

• if your deck has fewer cards remaining than your hand size, you can guarantee you'll draw the card in your next hand.
• if your deck is empty of a particular type of card, you can give yourself a chance to draw it that you otherwise wouldn't have until you reshuffled your deck. Say you know you're out of attacks - you can shuffle attacks back in, so you a chance to draw them.
• if there's a specific card you like so much you wish you could have it more often. Tackle might be good enough, particularly solo. Spider-Woman's Contaminant Immunity is also pretty sweet. I really like Preemptive Strike and am happy to pay an extra 1 for it.
• shuffling cards from the bottom of your deck back up where you can get them sooner: Aamir Khan
• shuffling cards you don't want away from the top of your deck: Peter Quill or Gamora
• adjusting the contents of your discard pile. Remember I said you couldn't get your Crosscounters back? Well, maybe if you get your other Protection attacks and thwarts out of the way, you can get Crosscounter back with Conditioning Room a little sooner

Overall, I'd say this doesn't go in every deck, but there are good homes for it.