Muerta is a great Position 4

I have played with Muerta players, and I have played with her myself. And a trend I see is that if you play her as a Position 1, then you have lost the game. Even mid often does great until enemies get Bkb, and then they become useless 9 times out of 10. While her ult is great for survivability, it seems wasted on a core Position right now.

As a support, you are also able to get items like Arcane Boots, which allow you to spam her abilities. And when you get cast range items, her abilities become way more useful.

Deadshot allows you to use fear on high damage heroes for 2 seconds every 10 seconds. Since fear make enemies unable to be slowed, this makes enemies get away from fights a decent distance, that, without a movement ability, can take them out of fights for 4 seconds or so to get walk back. You can even get enemies out position by bouncing the skill on creeps, trees, or other heroes.

Her W is great at zoning out people or keeping them disabled. You place it down and if the enemy is inside, they are slowed. If they try to get out of it, they get silenced. And if they are out of it, they don't want to go inside because they get silenced and slowed. Overall, a nightmare to deal with early game, and annoying late game. It is like a worse Disruptor ult, but with a third of the cool down.

Midgame, the level 15 talent makes your deadshot shoot from half the map away. This allows you to split push safely, since you can aim trees and direct the projectile while hidden. And at level 20, when you get the second Deadshot, you can split push faster and help more in fights.

Her playstyle feels a bit like Hoodwink's, just that you are way less mobile, but with more range with your abilities. And even then, you get a Force Staff, a Blink, or a Glimmer Cape, and you are suddenly a nightmare to catch.

While her ult and E don't add much from the support position, the built-in ghost scepter does save her having to buy it to survive. This is 1500 gold that supports have to spend often in mid game, that she doesn't. It allows her to get other items that help her team faster than other supports. It also allows her to right click physical damage carries, something a support is almost never able to do safely.

Her E, which is arguably her worst skill as a support, can help if you get lategame, after support items obviously, and build Maelstrom into Gleipnir. Then suddenly you deal a lot more damage that it's expected from a support. This, together with her ult makes her a mobile turret that the enemy Position 1 will ignore, since they can't hit her for 8 seconds. And if the enemy gets a Reventant's Brooch, or an early Bkb, then congratulations, you made the enemy core waste gold in an expensive item for a support.