The dog/crab root is channeled (pet cant do anything else for those 4 sec), it also has a slight delay and can only be used in melee range. All that makes spider web far superior to those two.
You should use a moth (4sec spell school lockout, ranged) and two debuff pets one with melee and one with spell casting debuff.
The two remaining slots i would fill with whatever buff pet your team needs for pre buffing (just use the 2 min ones) or a crane/monkey.
I wouldn't recommend root pets to help ease landing traps. It is simply not necessary with narrow escape, and a monkey/crane does that job just fine aswell as being able to prolong a cc chain a little bit longer.
huh? Pin/lockjaw works like this ;
A- you press stuff.
B- pet either runs over to or blinks to the target.
C- pet starts channeling pin or lockjaw for 4seconds, the cool-down of the ability occurs.
D- during these 4 seconds the pet can do no other action, if it does it breaks the channel and then the root is broken.
E- If the root is broken by other means the pet just stops channeling.
F- you will have to wait for the ability to come off cd again to use it again.
It wont re-root a target.
Dogs/crabs are just bad, not the worst pets imaginable to use but still close to useless.
Compare it with a spider;
This root lasts 5 seconds (1sec longer, not channeled)
Has a 30 yard range, means your root always will be instant if the pet is in range.
And worst of all the abilities both have the same cooldown.
Meaning a spider is better in every way imaginable.
Balanced right? When it comes to hunters Blizzard never seem to give a shit about stuff like this they just nerf whatever looks good.
Ok, i was thinking that the pet reroot the target during the channeling (if target break the root). Like monks fists of fury you get restunned if you break FoF stun while channeling. But ok if it is like you say my dog is really useless then. So crane looks still best for mm and i really hate cranes. Silence isn't that good in my mind, just because of DR with Silence Shot
Moth is an interrupt not a silence so no dr. Think rogue garrote (silence) and kick (interupt).
Crane is good, but you should give moth/fox(melee teams)/goat(caster teams) a go.