Thanks for the blog post about how annoyed you are at a talent. It was especially well-placed in the thread discussing DPS simulations.
DP can be incredibly irritating on some fights. Leady Deathwhisper being one where my pet was out of Line of Sight all the time being behind her and me at the bottom of the stairs. (Similair situation sometimes on Saurfang too, especially when trying to stay x range from other players and in range for DP).
Some fights where you would use LT during movement phases are a lot harder than with DP. Moving from fires on Icehowl, Legion Flame debuff on Jaraxxus, any add kiting you may have to do on Saurfang you are usually running away from the boss, thus out of range of your pet.
And if you do have a phase like this and you DP twice fast just to top yourself up, your pet goes oom.
Not that you cant lifetap of course, but it's less "bang for your buck".