You could say "time will tell" if we appointed Klopp instead of Ole. Ten Hag is undoubtedly a top coach. He has achieved excellent things at Ajax, and you see the early signs are fantastic already. Of course, time will tell, but it's not a random baseless hope to just say "Ten Hag is a big step up from previously relegated at Cardiff Ole, or interim manager Ralf with MLS level coaching staff". We had absolute garbage as our coaching staff the past few years. So it's not a high bar to beat. So of course, we will be massively improved, especially as Ten Hag is actually just a top coach.
Recruitment is crucial, I agree. But we will be massively improved from last season anyway even without anything else. Will we be improved enough relative to the others is the question. Conte and Tuchel are also very good coaches, and Tottenham has had a good window, while Chelsea to me is looking more likely of a collapse season than others so far. Arsenal have made good signings and have some momentum, though I don't rate Arteta much, at least not yet. And then there is Klopp and Pep, the top 2 coaches at the #1 and 2 teams in world football with their squads as well. So nobody is touching them yet. But I have no doubt that Ten Hag is the best possible manager we could have appointed, and I think he has the potential to get us to the top. But we need the recruitment right to get us there.
Basically, we might still finish 6th, but we could improve massively and still just finish 6th because a lack of options up front and others doing really well as well, and 3rd to 6th being a very tight group at this point. Just like we finished 2nd under Ole and I don't think we improved from the previous year when we were 3rd, or when we finished 2nd and I thought we were worse than when we finished 6th under Mourinho. We'll see a huge improvement this season, but where it will take us in the league position at the end of Ten Hag's first season remains to be seen and a lot probably rests on the next month. But long term no worries from me as we'll get there with ETH, just won't be instant.