I'm not to sure how much he rates Barkley. He went after Sigurdsson last summer too.I would say Sandro, Klaassen, Rooney, Giroud and Siggy would give us many more attacking options than what we had last year. Del was out on loan, and the team were simply playing to Lukaku's strengths.
Ron didn't rate Del (there's a long list of managers who felt the same) - he would have liked to have kept both Rom and Ross but they both wanted out. We got good money for Rom and we will get as much as we can for Ross.
As for Rom. I think he respects what he's good at and tailored the team to suit him but I don't think it was an easy fit hence how dire we were at the start. I think we will see a Koeman team for the first time next season.