So I think it is situational but I tend to go with this build but first is Gather Materials, which when dealing with clockers which we now have several is paramount to survival. Even with this I end up toping off the DPS, I think if you are going to Rift Shock at 7 when going with Warp Resonance at level 1.

I totally agree with most of your picks. Warp Resonance and Turbo Charged are basically mandatory for survival and any decent amount of damage, though I have considered Echo Pulse for the flexibility of activating poorly placed Warp Rifts.

I find it a little odd that you recommend Tower Defense for lvl 7 Talent considering just how weak his cannon appears to be. Especially considering how eager people are to try to kill it or shut it down (and easy it is to do so). Often I find it more as a distraction than anything else, and not worth the damage bonus of Rift Shock, especially paired with things like Shoot 'Em Up at 20.

The one credit I would give Tower Defense, is that it does make it much easier to take merc camps, but in those situations I'd be more inclined to use the shielded pylons to front the damage, using the cannon more as a protected damage assist.

I also think that Shield Battery is kinda flexible. It depends on the rest of your team, but particularly in combination with mana-hungry heroes like Lt. Morales or Li-Ming the Power Overflowing could be a better option for team fights considering the lack of build-up required before having an effect.

Lastly I'm personally more inclined to pick Gravity Well for 16, if someone is stupid enough to walk through it (or you force them to do so) it's gets almost as strong as his Null Gate in area denial for escaping and for picking up kills.