Kashrus is a huge issue. I would venture a guess that most programs, even the best hechsheirim, end up having at least one major issue over yom tov. I've spoken to many head mashgichim about this.
IME, kashrus needs to be split in to two categories.
1. Basic kashrus (treif venue, kashering, basar bchalav, treif, chometz, etc.)
2. Hilchos shabbos & Yom tov
In my years of experience any hotel that has kashrus concerns with the first category has a lousy hashgacha with poor planning , lack of cooperation, and not enough mashgichim.
On the other hand I would say that even the best kashrus at hotels use some kilos in terms of Hilchos shabbos and YT