A Kolarov/Clichy hybrid would be the best left back in the world, a perfect complement. Same probably goes for Zaba/Micah as well. Guess that's why managers structure squads like that purposely though, with players in the same or similar positions possessing contrasting traits & abilities in order to diversify.
It's important then to know how to use them and further more when to use them in order to bring out their best. That's obviously the tricky part and the one that brings managers unstuck. I feel Mancini sometimes did Kolarov a disservice by playing him on the wrong occasions.
Kolarov is perfect for a team like Villa away (better than Clichy imo), and for teams that don't press high & offer room to manoeuvre. Against Bayern, you'd use Clichy 9 times out of 10 with their pressing & attacking threat of Robben.
I've previously been a big critic of Kolarov's but if Pellegrini can use him the right way then I wouldn't mind if he stayed.