Pros
Very high burst
Enemies can't usually escape
Able to poke and zone enemies
Cons
Very squishy and usually focused
Relies on a partner for bursting
Not a pro/Not a con
Doesn't really cc if you dont go for but her passive makes enemy slower as long as you keep attacking.

*Note: I don't really feel like making a list of "threats", assasins like Nova, or Zeratul should kill you with a couple movements (If they know what they are doing of course...) this doesn't mean that you can not counter them, the "threats" are basically most of the assasins.

Levels
1:
Winter's Reach the extra reach makes the escape so much harder for enemies.
Lingering Chill i wouldn't recommend it for this build.
Deep Chill i've read guides and they recommend this talent, but i don't think +5% slower movement will make any difference, in that case i preffer extra range with Winter's Reach.
Conjurer's Pursuit i personally don't find this useful.
4:
Frost Shards not useful unless you focus your build on the Frostbolt.
Snowstorm since my build is based on Blizzard dmg, this is the best choice, you will hit more enemies.
Arcane Intellect could be useful but.. there are better choices.
Envenom many people recommends this, but i don't think single target dmg will be better than extra Blizzard radius.
7:
Ice Floes could be useful combined with lvl 16 Northern Exposure or Numbing Blast.
Frostbitten usually recommended, 15% extra dmg is quite a lot.
Frost Armor i would pick this just in case you have problems with an assasin like Zeratul or Illidan still, this talent doesn't make much difference.
Ice Lance not useful unless you focus your build on the Frostbolt.
10:
Ring of Frost i would pick this if the enemy has a lot of melee heroes, since you could hit more of them at once.
Summon Water Elemental i would pick this for extra dmg in case your team already has enough cc.
13:
Storm Front i recommend this since you won't have to get that close to the fight for casting Blizzard, so you will be safer.
Improved Ice Block recommended when assasins don't stop focusing you.
Icy Veins can be useful, especially with Frostbolt focused builds.
16:
Snow Crash useful, extra wave, extra dmg.
Northern Exposure maybe the best choice, +25% extra dmg, go for it.
Numbing Blast will give you a chance of escaping from assasins.
Ice Barrier could be useful, but there are better choices.
20:
Cold Snap i don't find this very useful...
Wintermute could be a possibility if you pick Summon Water Elemental for extra dmg.
Arcane Power i recommend it, since you recover part of your mana and you gain extra dmg.
Bolt of the Storm could be fine for escaping or re-positioning, but i don't like it personally.

*After a lot of games testing who would be a good comp with Jaina i've come to some conclusions:
I would put Jaina in the group of the heroes with the highest burst but in my usual build i depend on Blizzard dmg, and this skill takes a few moments to be completely useful, so we will need someone who can root/stun our enemy.*

I fully recommend playing with atleast one friend, or you won't be able to do your "burst" as you would like to do it.
Arthas: My best comp so far, early/mid or late game, is Arthas, can cc Howling Blast, while dealing nice dmg, especially with his passive Frostmourne Hungers and he will be tanky enough for taking some dmg.

Muradin: Another good one is Muradin has a great stun Storm Bolt and he's a nice tank, the only con i can find him is that he doesn't have the same dmg as Arthas and this could be a problem in every state of the game, so i would keep him only for 3 people comps (still nice tho!)

Uther: As well as with Muradin, the next comp, Uther doesn't have as much dmg as Arthas so i would recommend it for 3 people comps, but he has a nice stun Hammer of Justice, can heal, and in case that you pick Ring of Frost his ult Divine Storm can be a great play.

Kerrigan: Having Kerrigan as comp will take some time until you compenetrate, her stun isn't as reliable as Hammer of Justice for example, but the burst will not be a problem once you practice as a group.

I have also tried to comp with Malfurion and Tyrande, but their root/stun weren't as effective as the ones that i mentioned before. Could they still be used? Of course, they have nice support skills but you will have to find another way to make your burst work.

*The heroes that i mentioned before are the ones that could be used for 2 people comps (some are better for 3's but could also be used) and i have only mentioned the ones that i have tested with a partner during a long time.*