My opinion so far
The interesting thing would be, besides the stats, the CONTEST these ships will be introduced.
It's been said that both Tasha Yar and our old good (well, maybe not good) friend Franklin Drake - or the Klingon Intelligence for the KDF - will have something to do with the Ambassador and the Kamarag. My guess is that those two guys will give you a mission to investigate the fate of the "C" and (on Qo'Nos) of the few Kamarag prototypes. So I think that you'll have to do another "Slingshot" like on Night of the Comet and go back to the 2340s at Narendra system. You'll probably find that both the C, once disabled and almost destroyed, and the Kamarag prototypes will be stolen from the Romulans and brought to a romulan base where they'll be split into hundred of parts and reverse-engineered piece by piece, but there's a problem. Let's say both classes were carrying a top secret prototype device that, in romulan hands, could destabilize the Alpha quadrant and change the timeline (and let's say these mysterious device will be the special consoles of the two ships). So your task is to punch some romulans and steal the Enterprise (if you're FED) or the Kamarag itself (for the KDF) - here the best would be "Stealing the Enterprise" soundtrack by James Horner although they said in one of the last ask Cryptic they aren't allowed to use original scores yet - Then you have to fight some outdated warbirds and recreate the temporal anomaly which sent the C to the 2260s as seen in "Yesterday's Enterprise" with the help of Tasha (who will be beamed away from one of the dirty warbirds just before you enter). Back to your timeline you'll be awarded with a newly built Ambassador/Kamarag to fit properly that special device but with 25th-century systems (though original bridge) and the specs for a hybrid cruiser/escort or like the Vesta has been sci/escort
Something like this:
COM Engineering
LtCOM Tactical
LT Tactical
LT Science
ENS Universal
Or maybe use a similar layout to carriers where the Boffs are 4 instead of 5 so we can have another LtCOM universal (carriers in fact have TWO LtComms)

And make the stats Fleet-level
Devices: 4
Hull: 40500
Shield mod: 1.1
Special power: Ambassador +20/30% damage to phaser beam arrays (as the Ambassador was the first Starfleet ship that could equip phaser banks)
Kamarag: better manueverability and a COM tactical instead of the COM eng
Turnrate: Between an Excelsior and a Vesta (remember although the Ambassador is larger than an Exccelsior - but I'm not sure of that as in Memory Alpha it's said the Ambassador has 33 Decks and the excelsior 34 - engines evolve so it should have a turnrate of 9/10 but just a bit less inertia rate than the Galaxy; not sure what the Kamarag should be)
Then after 2 months (April/May or when S8 launches) make the ship available for 6 FSM or 4 FSM then the console available with a separate purchase at ca. 750 ZEN
Again, these are only speculations (I wanted to include Dual Cannons support but then this ship would be a bit OP being a free ship)

Like we really need another overly tactical cruiser.... Yeah right.

the feds don't really, but if it has just a LTC sci the ambassador could be pretty dangerous. a tactical focus with all the klink cruiser maneuverability and dhc use, well, there cant be to many of those actually

I remember you backing up my Boff Layout for the Ambassador on OPVP before. so its all good.

It would be hillarious if Ambassor would be a better (see more dmg / tank / sci, whaterver) cruiser than the Galaxy-R.

I can see a T3 Ambassador with a fleet retrofit, but not way should it better as Galaxy. But I guess Cryptic will do anything for money, even **** the canon.

I see your point.
A sci version would be fine too, but I really hope it won't be a full cruiser: in STO cruisers (although many like me have fun with them) aren't very useful, especially in PvE. Sure, in PvP they can be more useful but they are truly an "optional".
So I really really want it to be something more escort-oriented, not a copy'n'paste of the Regent by the way but something that can be easily used from all 3 careers more or less.
However I'm more curious about HOW they will introduce them as I said before. Opinions?

according to the stahl interview released today the anniversary mission will not only be available for a limited time, it will always be there and give the tier 3 ship. doing the mission during the anniversary will give the tier 5 ship though!

stahl also said he loves it and has flown it and it really sleek and has a lot of phaser firepower :O

What did you think of what he said about the Ambassador... "A lot of Phaser firepower" and what that means for what these ships may potentially be?

well, it proboly dealt with pve content no problem so hes impressed

But that's not as much fun as the Galaxy folks having cows by saying it's more than that.

Still, it could be as simple as him saying it's not a Lt Tac 2 Tac console Cruiser...