Yeah I still don’t like the third act unfortunately but a few days ago I rewrote it for fun. I really didn’t like that they felt the need to make the battle so large in scale so one big thing is that it’s scaled down. There is a few things I kept in, some even I didn’t really like all too much but kept for progression purposes. So some spoilers ahead. Let me know what you think if you decide to read it. 

Once again some minor spoilers from the actual movie :)

Only other change - (Taskmaster’s abilities are not just technology but a serum created by the scientists similar to their super soldier serum. Taskmaster serum gives the ability from the comics. Didn't hate that it was tech based but the power is cooler.)

Main rewrite - After the team has been captured Melina has been revealed to be helping Drakov and the Black Widow Program . They are brought to the RED ROOM. A facility built into a mountain, the facility is a few stories high, the lowest level being a hanger for planes, helicopters, and other vehicles.
One of the floors in the middle of the building is housing Alexi and Nat, while a floor above is testing on Yelena so that they can figure out what part of the brian they can fix to prevent the other widows from betraying the organization. Melina meets up with Drakov in his office on the top top floor of the base. They are discussing their next move and how they will grow their army to make an attack on the Avengers now that the team has been whittled down to just Tony, Rhodey, and Vision. It is then revealed that Nat and Melina switched positions and Melina helps Alexi break out. Natasha is aware of a condition in her body that prevents her from attacking drakov (this is told in a quick flashback, either one or two total but no more). Drakov notices that they have escaped and sends Taskmaster after them, Natasha breaks her nose to cut off her senses so she can actually go after Drakov, but he is slightly enhanced with the russian serum given to Alexi and he kicks the table forcing Natasha to the ground and gets a chance to escape. Nat runs after him and sees him at the end of a hallway but guarded by a small group of Widow Soldiers are guarding him, the sound of a group running starts rumbling behind Nat and she turns around to see more Widows, Drakov runs away and both groups run at Natasha creating a claustrophobic environment, also could be used as a small homage to her fight scene in Iron Man 2. Yelena is told that there is a small knife to free herself so she cuts off the straps holding her down and takes out the scientists that were about to experiment.

Taskmaster enters the room with Alexi and Melina and the fight begins. Taskmaster pulls out every trick in their bag, Panther claws, bow, grappling hooks to represent Spider-Man, and more. They are struggling to keep up with Taskmaster's speed and reflexes, both get cut up and Alexi even loses his helmet. As Yelena breaks out of the hospital area (in a one take sequence) we follow her take out soldiers in a hallway as well as a staircase, this goes on until she gets to the room where Alexi and Melina are fighting Taskmaster. They beat Taskmaster by teaming up and doing some sort of cool kick thing and they are able to crack the visor (visualized by seeing a close up Task coming into frame and hitting the ground and we see chips of the visor slide across the floor. Nats' fight with the widows ends up back in Drakov's office, At this point Yelena, Alexi, and Melina are down in the hangar fighting their way to a plane but they see Drakov also trying to leave on a helicopter. Melina breaks off from the group and goes after her. The soldiers began shooting at her and she got hit a few times but he was able to be fast enough to shoot and connect a grapple hook to the tail of the helicopter to the ground. This causes the helicopter to spin out and crash. Drakov is able to jump out in time before the helicopter explodes and weakens the few floors above it including the office. The floor begins to crumble under Nat but she is able to run fast enough and jump onto solid ground before the ground disappears. As Drakov tries to toss a grenade near Yelena and Alexis, the debris crushes him and to top it off the grenade explodes as well.

Natasha grapples down to the hangar floor and on the way down, Taskmaster jumps at the grapple line and follows her. Right as she touches the ground. Taskmaster swings, jumps off the wall and kicks her. Natasha gets a good look at Taskmaster and notices the armor is extremely damaged from the explosion and we finally see just an eye covered in shadow, Natasha finally knows Task is human. The fight is brutal and bare knuckle, Since Taskmaster is so injured they can’t really use their ability to its full advantage but it’s enough to still be a challenge and possible to block every move. While this is happening Alexi and Yelena take out the rest of the soldiers followed by Alexi pushing some rumble out of the way so Nat isn’t trapped outside. While this is happening Yelena moves the injured Melina onto a truck and runs over to Alexi to help push the rubble. At this point the entire facility is on fire and the structure could collapse at any point. Nat and Taskmasters fight moves around until it gets to the edge of the runway, below is a massive drop until it reaches to ground. After a while Nat is able to get the upper hand and is able to kick Taskmaster off the edge and all she feels like doing is to lay down and take a quick breath, but there is no time as Alexi and Yelena shout out her name, Nat tilts her head up and notices the structure is unstable. Alexi stays and waits for Nat as Yelena starts the jeeps and backs up near Alexi. Nat is booking for them but it becomes too late for Yelena to stay there so Alexi tells her to leave. Nat shoots her last grappling hook and zips up and flies through the opening Alexi made. The two meet up and sprint to the exit. They are almost crushed to death right near the ramp up to get to the ground level but Alexi is able to hold it long enough for Nat to slip through and for him to toss it and get out safely. We are then given a moment of quiet between the two, he was able to explain himself to Yelena but not to Nat, so he opens up and apologizes to her and they have a heart to heart. All of the heroes are reunited and give a group hug, all scuffed with dirt, suits scratched up, and just looking to rest for a bit. Melina starts to cough and chooses to lay back down in the seat. She unfortunately has lost too much blood and passes away in Nat’s arms. Ross and his team are seen in the distance, Nat says her goodbyes, Yelena gifts her with the vest and they make their way out. The cars pull up to Nat in a close up on the back of Nat’s head the camera pans down showing her pull out a baton the shot ends with a shot of her hand holding the baton and the screen cuts to black right as she extends the baton.
 
The final moments of the film are the same as the films ending with Mason gifting Nat with the quinjet.    

Post Credits Scene.
Theatrical End Credits is moved to a Post scene after stylized credits similar to the silhouette of the teaser trailer.

End Credits scene.
Close up on an eye opening, it’s Taskmaster. Cuts to a wide shot of him laying on the ground with the built in parachute from his suit laid out on the ground. Task struggles to stand up but they manage to and the parachute is detached and the scene ends with them walking away, their real identity to be revealed in a future project.