lol... cast heal even when it doesn't need to be cast... that's awesome Mazi... such a comedian. But seriously, bubble/renew is fine to cast and can often mean the difference between whether or not a target dies. 2 instant casts to keep them up, binding, Greater Heal or Serenity Heal and you're laughing.
I suspect while you're wasting time casting useless heals you're not moving, so the instances where you'd be standing in fire etc would be very high.
Mazi despite the fact that you can recover the cost of throwing Heal spells around constantly, you're ruining the rate at which you recover your mana fully, seriously its like the worst idea ever.
-sigh- Please read things fully. You haven't a clue Why would you cast Renew on someone if they, potentially, are going to die?
I use Grid with mouseover macros & Clique for dispelling (alt+shift, and alt clicks) & PW:S. I think either having Clique or Mouseover macros will improve your performance a lot. It might not make that big of a difference with 1 cast, but over the course of a fight it really can be a huge boost in throughput.