Not gunna do my old school choo-choo's but I'll just go in order
"Why is it an Ability not a trait"
Because it's only logical to expect a negative side effect that SE doesn't want us to spam back and forth between the 2 options, and assume we'll just choose one or the other. I'm thinking along the lines of Hasso/Seigan and whatever the new Nin 2 abilities were. But instead of giving us 3 choices (depending on part 3 of the update) we only get 2. Normal avatars where we can BP>Release>Repeat in a DD role (loose term) or Weakened Avatars that support the party.
"Will the pet get the buff as well"
Assuming the above is the way it will actually work, I doubt the pet will get the buff, although a weakend pet + a buffed pet = back to a normal strength pet? It will all depend on what the 'weakened' pet will constitute. Few Idea's already thrown out, BP timer, Smn skill, etc etc.
Looking at a few of these, My first guess, and probably (imo) most preferable, is double blood pact timers. At first thought there will be a lot of complaints, but assuming most of us are near 45 second recast as is, we're only looking at 1:30 timer. That's not really that bad when considering any of our Ward's normally used. In fact, it fits perfectly assuming our durations are 3 minutes. All buffs will still be active as before with no change. Hastega, Howl, and any other party buff used, is expected a 3 min duration, and your recast won't matter, unless you're keeping 3 wards on as is, and there are very few of you who do keep 3 buffs active. The reason this is my first guess, is because it's the same concept as hasso. But again it's just a guess.
Second possibility, someone mentioned a reduction in Smn Skill. While this would solve a handful of complaints of "Why did I spend this much time/effort getting 340+ Smn Skill, if I see no effect after the ~310 mark on anything but Siphon?" A percentage cut to Smn Skill would emphasize the need for the better gear to reach the Smn skill needed under the negative effect. While I won't write this idea off, it's less likely to be implied, because SE won't like the idea of All the positives of the job ability, if the negative effects can be negated with enough +Smn Skill gear/merits.
Other possibilities, lower attack/accuracy, or a more delay. I don't foresee SE going through the work of alternative tables for avatar acc/att for this ability, but slowing the avatar attack speed down would be as easy as applying a constant 'slow' effect which would be easy, but again, I doubt this will be the actual down side, but who knows.
Going back to my first guess of double the blood pact timer, let's take a look at the other side of the spectrum. First I'll just say, yeah it will suck for wards like sleepga from shiva when we're solo'ing etc. But lets look at the Rage side. For anything End game, where Smn are the main DD, yeah, it'll be no good, but for party situations or other events you have to see the bigger picture.
We're comparing BP/Release 3 times a minute, vs 2 BP + 3 minutes of melee dmg, lower perp cost, and a party AoE bonus. That's not a bad payoff, and I've even willing to bet, that on merit mobs, 3 minutes of melee damage will be near the damage 1 BP provides on average.
>> Quick math side note << 320 delay = 5.3 seconds, 3min = 180sec 180/5.3 = 33 melee swings, 33*70%acc = 23 hits. (celestial based on enil's melee threads on birds)42 Damage a hit would mean 966 Damage in 3 minutes. Which more than likely is what you're probably averaging with most 70 Pacts. Assuming the lowest cut in perp is -1tick, 3 minutes, is 60mp. So for 100 less MP you get the same damage expected. Which looks good on paper, but 3 minutes of avatar out means zero /healing. So, you're actually losing MP overall, but not nearly as much as you'd think. We can get into the melee'ing with spirit taker discussion if you want, I'm not really up for it. But It's hard not to expect anyone to have a -3 Perp Fay Crozier by now, which has a decent 50 base Dmg, which isn't too horrible for Spirit Taker, espesually if you're macro'ing in Mnd/Int. But like I said, different story, different time. And then you have to start fighting the 'omg tp feeding' issues.
Side Note>>> Fenrir's expected melee dmg is 52 per hit, and he attacks @ 4.6 seconds, which is 39 swings in 3 min @ 80% acc = 31 landed hits = 1612 damage in 3 minutes. WAAAAYYYY more than you can expect from a 3rd Eclipse bite. And that's based on Merit Mobs. Add in the fact fenrir is already the cheaper avatar and you're looking at potential, but his AoE effect is not as desirable, but Ecliptic Howl can be useful for the Party. Again on the Melee thing, any avatar other than Garuda allows you to use Walmart Turban, and 5% haste is a chunk to gain when considering melee dmg.
For the Solo'ers... Assuming option 1 is correct, this will be huge. I can't see any down side to this for you, you should all be jumping for Joy. Especially after reading what I wrote above about Fenrir's DoT and MP. Also take into consideration, that the damage will be more than double above when applied to EP/DC mobs, due to the higher avg melee as well as higher Acc rate.
For the General Smn's, you wanted lower perp cost, and incentive to keep avatars out, congrats you got it. If you expected it to come without any downsides, be realistic. Although I agree even with zero down sides to this ability, I didn't see it being over powering, but, such is life. And as a 'hybrid' job SE is always trying to push us into 1 choice of 3 roles. No downsides would allow us to do multiple roles. This gives us more tools to choose between the 3. End Game DD won't see any change, but our healer and support roles will be more viable in game, giving back some options we use to have.
For the Main healers, If you remember the relief you got when we were given /sch for Regen 2 in merits, this is even better. We just got Regen3GA with no mp cost. Free, FREE carby WITHOUT the need for a light staff, means you can use martial staff for your spirit takers, and /healing shouldn't be an issue. You get to keep Carby out for 3 minutes at a time (assuming you're still going to be hastega'ing) and shouldn't run into any MP issues even with /whm casting the occasional cure 3's. I read a lot of people say "I wouldn't mind being the party's b*tch/healer if I could at least do it with my avatars because that's why my jobs suppose to be about!!!11one1!!" While not everyone agrees with this, we can all certainly agree it's a large step in the right direction, and even is support roles, running around with carby will always be a regen 3'ga
For the other kind of solo'ing... Carby Kiting!
Guess what? HUGE update for us as well. Hate Free Regen 3 on (lets say half the time) Obviously you won't be in range for regen constantly, but there's no reason you can't stay withing Regen range until <pethpp> reaches 50%, plus we don't always need hp. But this will definitely help in the extend carby kiting situations where casting carby over and over, slowly builds hate over time, and carby doesn't pull hate back after the first hit or two (or miss or two if you have my luck, lol)
Again, the above is all based on the assumption the only downside is BP timer being doubled, which as I said, I think is the most preferable downside listed so far. Well... Actually the -smn skill would be the easiest to overcome, lol. But for that specific reason I don't see it becoming the implemented downside.
Wall o text, but I've been quite for a while. :p
75 RDM BLM SCH SAM PUP