I am going to go a little deeper in my reasoning (now that i have secured the first post spot)
My biggest problems with this topic involve getting insta killed by pets. The process almost ALWAYS involves the following:
1) A stealth archer dismounts me with a heavy xbow.
2) A stealth tamer summons pets, and all kills me.
3) I start running for dear life on foot, waiting for my no-mount timer to expire.
4) The tamer keeps pace with me in speed animal form, summoning pets one step ahead of me, effectively letting them bite me each time they are summoned.
5) I die.
(I am very familiar with this process, as I also employ it as the stealth tamer frequently).
Looking at each step indiviually, I can say the following:
1) Getting dismounted by a stealth archer hurts, and sucks, but ultimately is not my final undoing. The archer by him/herself cannot deal enough damage to kill me without me getting away or scaring them off. I have many time easily gotten away from a lone stealth dismount archer, no problem. I also have a good enough success rate of escaping a stealth dismount archer AND gank squad. Even on foot, I am mobile enough to evade hits from melee players long enough to get mounted, and mages need to stay still to cast the big damage on me, so between my self healing, pots, and running, I have a fair chance of escape (not near 100% of course, but at least I have a chance). As such, I think this step of the process if fine.
2) The tamer summons pets and all kills... Here is where things go down hill. The pets will most likely get a first hit on me before I am able to get moving, which is fine. On foot I can outrun most pets. So after that first hit, I can usually get out of melee range, and fromt here survive magic attacks until I am able to remount. So I feel the initial 'instant petball summon' is fine. A 'cast timer' or such would make using a pet in an ambush pointless, as I would be long gone by the time the timer went off (unless the tamer and dismounter were coordinated enough to have the tamer initiate timer before the dismount
, but in that case I give props for the skill). This step is fine.
3) me running... well... not much to say here.
4) The tamer pacing me summong pets... This is lame. Being on foot, it gets VERY difficult to outrun a mount speed tamer. I know it is possible to get away, I have seen people do it and I have managed to do it, but that is not very common. Now, if the tamer could not summon while in animal form, this means they need to keep pace on foot, which means they cannot jump in front of me to assure a hit from the pet. Awesome. And if there is even as little as a 5 second timer on pet balls, this gives me enough time to only take two hits (the initial all kill, and 1 summon 5 seconds later) before my no-mount timer runs out and I am speeding away.
4part2) Now some problems I can forsee with only using the no summon while animal form... Even with no summon while in animal form, I can imagine myself using the following tactic: stealth to target, wait for dismount, summon rune beetle, 'all kill', summon nightmare, mount, chase, summon rune beetle while keeping pace. Using uoa macros I bet I could do that pretty darn quick. So this is where the summon timer comes into play as well, I will still only be getting 2 hits in by the time the guy is able to remount.
4part3) problems with only using petball timer... I will be able to use 5 slots of damage instead of saving (at least) 1 for a mount. That *may* be enough damage output to drop someone in 2 hits (from each pet).
and last step 5) I die... well, not a lot to talk about this one either.
None of these situations consider larger ganks- which is fine. A 5v1 gank should be darn hard for the victim. And sure, ym getaways rely on having a mount following me as i flee, so if the attackers posion my horse i am out of luck, but even then I have managed to run away on foot from dismount+NO PETBALL tamer.
So again, I vote YES to no petball use while in animal form, and a small timer for using a single pet ball (not universal, I think u should be able to use two different petballs with no timer... or at least ui think this until someone convinces me otherwise).
EDIT: WHEN I SAY "TIMER" I DO NOT MEAN CAST TIME, I MEAN TIME BETWEEN USES.