I think I would’ve preferred to see another Toa get Krana’d instead of Lewa rather than alongside him. The Krana infection for Lewa was particularly underwhelming as after a brief spar with Onua, Lewa brute-forced his way through the Bahrag’s control and ripped the Krana off.
In MNOG, Lewa’s short-lived existence as Makuta’s pawn illustrated more than anything else that Lewa was the least powerful pawn he could have chosen. IMO it would’ve been cool to see Kopaka as the Krana-controlled one instead of Lewa, since the Toa of Air did absolutely nothing to assist with the cleaning, and Kopaka’s reclusive and distancing nature means it’s possible the Toa wouldn’t find out about his being turned until it was too late for the island.
However Kopaka also literally overpowered Level 6 fear Kraata by telling it No, so he would probably break free of the Krana’s control much easier than Lewa did.