He'd be horrified, I think.
If Zionism and history with surviving Herzl doesn't change much or any, he might be very dissapointed.
Based on what? The establishment of a Jewish state with it's own sovereignty and military? The revival of the Hebrew language?
Honestly, I think the thing he'd be most horrified by is that the socialists were most prominent political party.
...But it seems unlikely that history would have gone as OTL if Herzl had been around. As stated, he wasn't a socialist (though I can't find anything that says he disapproved of them,
per se), and I think he was more inclined to try and work with the Great Powers (while the Labor Zionists were, too, it can be argued that they started from an inherently anti-Great Power starting point, though in fairness the 1922 White Paper would make anyone feel grumpy and betrayed).
Let's look at events and consider how they might have changed:
-The first is the British Uganda Plan (which, as always, I feel obligated to point out was actually supposed to be in what is now Kenya

). I'm not sure that Herzl supported it, but he was the one who got it and brought it to the Zionist Congress. He died before it's somewhat controversial rejection, and may well have pushed it back before the Congress. Or he may have pushed for a territorialist state (i.e. not Palestine) somewhere else; he was a particular fan of Patagonia (potential Mapuche "Nakba" notwithstanding). Opposition to this idea was actually a [large] minority, but very powerful among that minority, whereas very few people felt strongly about accepting any possible Jewish location. Herzl could, hypothetically, have used his position as Father of Zionism to bully the Russians into line.
-Herzl might have been better at courting the Young Turks during the end of the Ottoman Empire/WWI and after, which has all kinds of implications
-Herzl would probably not having changed much going on in the actual settlement in the 1900-1920 period though; the founding of Tel Aviv, the establishment of the Hebrew U and the Technion, the increase in agricultural colonies were all things he approved of (though he didn't have the agricultural fetish that so many socialists did, I think).
-He'd probably have ignored the Bund, not wanting to get caught up in socialist internal politics
-If things go well with the Young Turks, he might resist British alliance in WWI; if not, he'll court them just as OTL, though maybe more effectively - for example, a Herzl-Faisal Agreement might be more successful than OTL's Weizmann-Faisal agreement.
-I'm not sure how I feel to discuss Herzl's views in the 20-40s. I suspect that he would have been initially against the opposition to the British, but turned around once it because clear how noncooperative London intended to be.