Van Wilder can do one day hilly races and classics just fine and has a ceiling that is simply higher than that of Honoré. He finished 13th at Lombardia (ahead of Honoré) first QS rider, he was probably the best QS rider (including Alaphilippe and Honoré) at Bernocchi. There are plenty of other races where he showed he copes very well with 1 day racing, like the NC, Primus classic etc. He is also not a pure climber/TT'er but a compact allrounder who pushes big numbers. He won Nokere Koerse as a junior and in his only year as an espoir, he finished 15s behind the winner in LBL and in the same time as the winner in RVV. He's plenty capable to ride classics and outshine Honoré in that department as well.
That doesn't mean i don't value Honoré, like i already said, i do. I think he's a versatile rider who could still be valuable in a classic QS "multi leader" approach, or as a superdomestique in both classics as hilly stages in a GT for instance. But i can understand if he wants to leave, considering the complete breakthrough of Evenepoel and Van Wilder also showing signs.
I think Hirt is a great addition, but he isn't Kuss or Almeida or the guy who will close the gap to Vingegaard or Pogacar with Evenepoel in his wheel. I'm also not saying they desperately need an extra climber immediately, just that with Honoré leaving, it opens up an extra spot. Yes, Van Wilder will get better, but he will also not want to ride as a domestique until the end of time. Vansevenant, i'm afraid he will not improve that much anymore. Masnada will hopefully bounce back and Cattaneo, if he doesn't ride in different races, is also an excellent climber to have on the team. I already said all of this in the Evenepoel topic many times, when people state the team is too weak to ride the TDF for instance next year.
I'm not even sure i would personally be looking for that type of climber anyway. I think replacing Honoré with a rider who can take up a similar role in the team might be better. A secondary leader in smaller races, or a big engine domestique in hilly races/stages (they currently only have Serry for that role anymore).