IMO they included Klaw to improve the White (marketing) quotient and then removed him from proceedings early in the movie.. It was a marketing finesse.
They could have left Klaw for BP 2 with no significant changes to the script, that is how little he did.
It would have been simple to remove him.
Just refer to what happened with Klaw in the past. Klaw was not needed for the robbery. Remove him from the sale. Erik could have turned up with just the necklace. T'challa and W'kabi's fallout could have been T'challa just refusing to hunt down Klaw or Klaw affiliates or vibranium thieves in general. Maybe have W'kabi be upset because his men have to defend the borders and his family/people are dying doing it. CIA could have crossed paths with Lupita during her mission or have Bilbo get shot during the botched sale.
Then more time could have been spent fleshing out Killmonger. Maybe spend more time on the 3rd quarter of the movie (when Killmonger became King) which felt a bit rushed. Also more time could have been spent on the subversive / spy element of Wakanda. The line 'did you think that we would forget you', the lip-markings and the secret society type elements were underused. Wakandans being everywhere, unseen and superior is something that has (had?) a lot of potential and should be used more.