No, that's being smart.Again, I've never had any issues whatsoever with Hagara or Spine. Hagara he'll sit idle while she's shielded, or run out to attack ice crystals/lightning elemental as long as I dropped the totem in a spot where range wouldn't be an issue, and once the shield is down, he's back on Hagara every time. Spine, same thing; if you drop him before a tendon, he won't switch TO the tendon because he's already got a target. If you drop it when the tendon's up, and anything else is closer, same thing. That's not AI problems, that's how he targets, and you as a Shaman player should know that.
Searing on Spine is absolutely fine. No AI issues whatsoever, so I don't know why you even raise that. The only people I've heard who have issues are those who DoT up the Bloods with Flame Shock before the tendon spawns, and that's player error, absolutely.
And no, Searing and FET don't share the same AI. They don't even share the same ownership; ST is your Guardian. The Fire Elemental is the Fire Elemental Totem's Guardian, which is your Guardian.