Edit 1:
Added Gameplay video

I'm not here to teach you how to play Sylvanas. I just want to help people pick the right talents, with all the "newness" that has been added to Sylvanas.

1. Sylvanas the Specialist is a team fight/helper build.
2. Sylvanas the Wannabe Assassin is the full assassin build.
3. Sylvanas the New Hybrid is a hybrid of the 2. This can be your default pick if you are unsure which route you want to take. It balances her out so that she is deadly and is a game changer for most matches.

All skills are the same all the way to level 13. Level 16 and 20 talents determine your role in the team.

Level 1

As cool as this talent sounds, as long as you always hold the Q button down all the time, this talent is worthless.
This talent is the automatic go to choice, since having long Black Arrow duration allows for you to take camps easier and slow down minion/merc waves for even longer periods, Additionally, if you are going for the Specialist build, then this will affect heroes too at level 16.
While this talent sounds cool, unless you are constantly with a minion wave the 50% doesn't amount to much. Don't believe me? Do a "Try it" session with Sylvanas and chose that talent. Just follow the minion waves without attacking. The amount of bonus damage is negligible. Still feel free to try it, if you plan on always being next to a minion wave.

Level 4

Having 1 extra charge of Withering Fire is awesome, but being able to do some burst damage makes this pick the one to take.
This talent is great if you want to keep back from getting ganked and play it safe. Use is situation based.
Got nerfed and Shadow Dagger build is not as powerful as it use to be.

Level 7

Unlike in the past this talent should be your number one choice for most maps.
Got nerfed hard and only affects minions now, but this is still situation based and should be considered for Tomb of the Spider Queen and Infernal Shrines.
This talent sucked at level 10 and still sucks at level 7. Don't be tempted in any way, shape, or form.

Level 10

Still the #1 pick in my opinion for Sylvanas. You cannot beat an AoE mass silence in any team fight.
While this is a crazy new talent and on the surface looks great, it's application and execution are poor. If you use this in a team fight, then consider yourself an easy target. This talent is only great, if you never plan on going into a team fight and you are fighting in a 2v1 situation.

Level 13

Typically only heals for one bar.
Got a huge buff by allowing you a free Withering Fire reset twice. You can take down bruiser camps at lightning fast speed and you can chase heroes if the situation is appropriate. Hello burst potential.
If you have to pick this talent, then you are a suicidal person to begin with. Sylvanas is squishy, don't get too close and don't pick this talent.
So situation based and not worth the 30 second cooldown. If you are using this talent, then you are probably dead already.

Level 16

The talents at this tier are great and some are situation based.

Necessary for running away from ganks. Use this to play it safe and be defensive.
Use to be the go to pick for this level, but got nerfed. It now only affects the first target you hit. If you pick this talent don't miss.
Pick this talent if you are going for the specialist build and want to be able to run away or help your team chase. If you plan on being in many team fights, then this is the talent for you.
Sylvanas now has potential to be a hybrid assassin and this talent piles on the damage. At level 20 this talent increases your DPS by 200. Huge game changer for Sylvanas.

Level 20

Such a great talent not to pass up. Help your team out and stop/prevent those ultimate's from wrecking your team.
Hopefully, you did not pick Mind Control, this talent is just not worth picking even if you felt crazy and picked Mind Control.
If you are going for the assassin build, then pick this talent for a DPS increase of about 100 at level 20. This will help you get those kills and make your team wonder if you are suppose to be a specialist or you are just bat crazy. It's okay to be crazy, mental health clinics are accepting new patients all around your community.
Again, if you are in too many situations where you are running, then you are probably not doing something right. If you really feel like you cannot get away, especially if you are a new person to Sylvanas, then maybe consider taking this talent. In the end, there are two amazing talents ready for your picking and you should just pass this one up.

Videos

Here is some gameplay of Nazeebo and I taking out camps rapidly on Garden of Terror: