I'd say they're merging Gendry and Edric Storm, same as Loras and Willas Tyrell. Edric has very little story at all, except in regard to the same aspect of his parentage that Gendry has, and even Gendry has had a very minimal role since Book 3. I'm pretty sure Edric Storm is out of the series in any meaningful fashion. For that matter Gendry's prior destination, the Watch, and the general attitude of the Brotherhood without Banners to fight for the people rather than a king could be worked into dialogue as a factor weighing in on Stannis's own course of actions later in the book.

Also, personally I've a suspicion Gendry is supposed to rediscover making Valyrian Steel, since he was apprenticed to one of the few people we know can re-forge it, Tobho Mott, and he's got that whole blood of kings thing going on.

I still feel a bit puzzled by the Theon arc, it's not bad, it works, but it does feel like cheap filler. One room, raw dialogue, unchanging props... perfect time-burner for minimal production cost, and definitely not helping with legit impression that GoT is overusing the graphic sex and violence thing, especially with this episode's addition to the 'extra reasons to hate Joffrey' list. Of course, except for the Wall, the entire episode was dialogue with no special effects, few people, and no new rooms, props, or scenery so the Theon scenes aren't the only ones clearly trying to save budget costs, presumably from using a lot up on Dany's sequence and the wedding's... of course that might play into the Gendry-Edric merger too, they seem to have avoided making up Storm's End castle scenery except for the somewhat bizarre bit where they have Davos smuggle Melisandre into a tunnel under Storm's End in order to... kill Penrose Renly in a tent... oops.

All in all a good episode and of course not every one can be action-packed but the last two have been kind of weak after the two before it which were easily amongst the best to date, so a bit of a let down.