Wing back can be one of the most important positions these days. We were never going to replace Vik with someone who carries the ball like he does, that would cost similar to what we sold him for or require a miracle finding an unknown with similar attributes.
The cheaper, and maybe better, option is to replace him with a solid striker like Simms, and two high quality wing backs who can bomb down the wings and create. Robins liked that system in the League 1 winning season with Dabo carrying the ball up the pitch so effectively, the box formation with O'Hare/Allen (attacking) and Shipley/Westbrook (cautious) running teams ragged and Godden finishing everything we create.
We might not have the talismanic presence of Vik, but if the overall team is more threatening, then it could be more effective, cheaper, and add a few more assets to make money on in the future. It's a lot of money for us to spend, but if it's the style we're going to use to replace Vik's devastating ball carrying capabilities, then it would be money well spent.