Good movie but doesn't elevate itself despite Fassbender

The Killer reminded me a lot of Collateral with Tom Cruise (who should've won Oscar) but more spread apart with human frailties and mistakes and the assassin thinking too much of himself.
So Fassbender is a no-name hitman who calculates everything but makes many basic mistakes and does things most hitmen won't. Such as lying in wait in one place in Paris for a week+ with bright lights and a window direct across in a Wework!
He should have done it this way -
1. wait for the old man to be done with the dominatrix and go to bed. The dominatrix would've left and the dude would have dismissed his bodyguard and then gone for a shower or bed and it would be quiet. Wait and then take him out or if he's worried about the blinds then get a thermal scope given his wealth or get him in one of the other open chances he got. His escape was pretty carefully thought out and done well and cops would not be able to get to him quickly with so many changes.
2. him taking out the taxi cab guy-why? because he drove them or was he involved in the sexual assault? But killing him there under a bridge in daylight in the open screamed amateur. Esp there would be random cameras around.
3. Taking out the lawyer was very well done and disposing on him and secretary who was taken out the perfect Hitman game kill was the best. Still he probably left many loose ends with cameras.
4. The Florida man fight was good. Dude was legit a beast and it showed. Getting best of him but then torching the house with a molotov was odd choice and would engage cops faster and again cameras would out him along the routes etc.
5. Tilda Swinton take out - should've been done lying in wait for her at her home. She clearly left for dinner and would be back. He could've done it without anyone risking seeing him.
6. Inexplicably leaving the final old man without taking him out was odd and then going back to DR was very amateurish for the 10,000 hr hitman.

I mean, maybe that's the point.
He's a killer but not even the best or such but just above avg. He's still thinking he's elite but he's clearly not. He's distracted and like people who do regular jobs and get tired of it, he's the same. He wants out but doesn't know anything else and is making mistakes.

Fassbender was awesome and the movie draws you in. Some hits were good and enjoyable but I loved the realistic feel and unpredictability of those. Things go awry and he keeps getting interrupted during his "anticipate, don't improvise" etc. bs. spiel he's going internally.

I rate this movie a very good 7.5/10. Fassbender was amazing and the directing and plot was tight and moved well enough. It was not unrealistic but felt quite likely given people ignore things and make mistakes etc.