As I'll have to stop saying at some point, my Dad is a Blue so I know plenty about Everton. I think they've done great business all in all and the fact that they've hardly spent anything (net) is a plus, not a minus.
Getting a decent keeper was arguably the top priority. Both of their keepers last term were woeful and Pickford could add 10 points alone. Keane is a top class addition too and the pair help keep a little bit of an English core at the back.
Sandro could well be the bargain of the season. His goals per minute ratio in La Liga was better than Neymar, Benzema and Griezmann. Not bad playing for the side that finished 11th! He's a brilliant all-round striker and has apparently looked sharp in pre-season. Schooled at La Masia you can be sure he has a good brain too.
Klaasen is a tough one because the Dutch league is poor but captaining Ajax at 24 to the Europa League final suggests he could be very good and he scores more goals (albeit in Holland) than Barkley.
With Everton's youngsters - Davies, Holgate, Calvert-Lewin and Kieran Dowell - as well, they have solid back-up and a decent squad. If they start the season well and get some confidence I definitely think they can challenge for the top 4.
The issue, as we found ourselves last term, is that the "Big 7" are now all spending huge sums and all have great squads. It's going to be an interesting season, that's for sure. Everton could finish 7th (or lower!) easily but they could even finish 3rd.
Edit - Sorry, forgot to say about Rooney, I think this is partly for his off-pitch impact and "the project" (as seems to be the modern parlance). His role with the youngsters but also in building the stature of the club globally. They don't have anyone anywhere near as recognisable or marketable.