http://www.independent.co.uk/sport/f...-a7837516.html
https://www.google.co.uk/amp/s/diffe...-part-one/amp/
As these two articles seem to show, sigurdssons main asset these days is his delivery from set pieces. Take that away and he's pretty average. Some parallels with Whitts there probably.
For £50 million you want more than just someone to take the free kicks.
Barkley isn't worth £50 million either, but I'd probably have him over sigurdsson.