Well, the reaso to go VH was exactly to speed down land grab.
As it is now, the land grab is completely unrealistic.
For example on Normal a duke can easily grab other dukes titles after a decade of prestige stockpiling.
IRL a duke could only make a claim on other duke if he had some ties or he was very influential in the kingdom (preferably having influence to king, who then wouldn't oppose such move)/
It also makes claims a lot more valuable as you'll be wanting to get each and every claim you can (claim events, claim holder joins your courts, claims through marriage, etc).
Even AI won't be so easy grabbing claims. Besides I've noticed that AI grabs claims intelligently on VH, for example king of Hungary in my latest game grabs only Austrian, Polish and Croatian lands, adjacent to his border.
I could consider changing agresiveness as there are problems ensuring AI doesn't attack small nations right away, but I would like to hear a better argument than 'grab only 5 nonpagan provs in 100 years', especially because this argument is not true - my latest game which I started as Navarra, I've already conquered every christian land in Spain, except a badly beaten Leon, and it's only 1114 (which is 50 years from start).
Also please note that one is not allowed to grab king titles anyway, so you wont need those 10000+ prestige. The biggest you could need to grab a duke title would be around 5000, but then you can always simply grab his counties one by one..
