This is specifically for SEN ofc because that's all anyone talks about, but it applies in general as well.
I would much rather have 5 players with no defined roles and good cohesion over a team with perfect roles that can't play off each other. Tier 1 players can pick up new roles in months, and obviously there's some agent specific mistakes and uncomfortability that people love to make fun of newish players for, but that hardly matters if the player is hitting shots and fulfilling their role in general. If SEN play better with tenz on smokes and with zellsis on the team, that's a good indicator that zellsis brings a soft element that matters more than tenz's role comfortability.