I think it would be a mistake to trade McI for the sake of trading him or to make room for Clendening. (of course if you are getting something of greater value, you have to go for it)
Right now, IMO McI is already a better all round DEFENSEman than Clendening with far less of an opportunity to play regularly in this league.
Clendening is a decent puck moving Dman, not great in his own zone and an asset on the PP. More to the point there is nothing special about him, players like him come along fairly often. He is not a difficult piece to replace. AND he has reached his potential, there's nothing more you are going to get from him.
IMO right now, McI is a decent third pairing Dman with a very good shot, better in his own end than Clendening, FAR more physical, a player that makes opponents keep their heads up and think twice, and a player that has shown flashes of genuine leadership ability. AND he may not even be that close to his ceiling yet. He hasn't had the opportunity Clendening has had, and he hasn't had the same amount of time to develop as other players his age due to injuries, on top of which larger dmen take longer to develop in the first place. There is a decent chance that McIlrath will become an important player on an NHL team, there is practically no chance of that for Clendening. Why on earth would you keep a far more easily replaceable player that has far less possible upside over a player that is harder to find and hasn't even reached his ceiling, when the players are already so even in NHL capability? I just think that's totally irrational. And I believe Gorton will see it the same way.
Anyhow, I guess we will find out soon enough.
BTW, be prepared for the Flyers to grab Dylan if he goes on waivers, if someone else doesn't first.