I have found from personal experience that macroing /petattack into all your shots or even just a few, is actually a huge loss in overall damage. This is because everytime you hit that macro, it is resetting the pets autoattack swing timer, this is evident if you use an addon such as quartz to monitor such things.
/cast Hunter's Mark
/petattack
Is sufficient enough so it's not being spamming and constantly resetting the timer with each shot.
On the point about survival not having a stun for adds on ragnaros, this is true, which is why I use a modified pet build with charge and have that as a macro just as a fallback, because doing 25 mans there is sometime some confusion on who is stunning what add.
http://www.wowhead.com/petcalc#0md00ccz0hoko is the spec I use on a cat just for that fight