Gonna be honest. I don't really miss Sustain, and I would rather they simply allow your pet to be healed for a percentage of your DPS if they needed to do that.

As for the changes, I'm not terribly surprised by this, if only because it's inevitable. They wanted Summoner to "feel like a Summoner", but they didn't put in even half the tools necessary to have Summoner go that route. So now they have to buff the Warlock part of the class because, it turns out, you can't just slap one summon on the class while lowering damage sources everywhere else and pretend that the class is now what you always envisioned it to be, even though that's not what it was for years. They could've just buffed the Ruins instead, but the fact that they buffed the DoTs is telling.

As far as I can tell, they don't know what they want the class to actually do. Chances are, they won't in 4.1 either. I'm embracing BLM in the meantime.