I just wanted to bump this topic, because I feel like site manipulation is currently a highly-abused strategy with some of the post-Shadows formats. I've been seeing a lot of decks that are geared to play the same site over and over again, constantly replacing it, and then replaying it again, to achieve effects such as the opponent having to wound/exert his fellowship over and over, the opponent only ever being able to assign one minion per companion, the player getting to heal several guys with every move, etc. I'd really like to see this strategy get depowered a bit. Maybe I'm wrong, but when Decipher made those cards, I don't think they envisioned people playing the same site over and over again every single move.
So here's a thought: Most of the "play the next site" cards include language along the lines of, "replacing OPPONENT'S site if necessary." OPPONENT's site, not the player's own site. Any chance of a ruling that such cards can only replace the opponent's site, and do not work when trying to replace the player's own site? I feel this might check the abuse I currently see.
Of course, a blanket rule that you can only replace a site that you didn't play yourself would be even better, but I acknowledge that this would be a brand new rule. I think a somewhat stricter interpretation of the "opponent's site" language would perhaps be more palatable.