iserith
Magic Wordsmith
That's the crux of it; if a DM wants to rule it a certain way in his campaign, that is perfectly acceptable and fine, and it might even work sometimes and NOT others and that is also the decision of the DM. Maybe this succubus charm can be dispelled, but no, this vampire's cannot, it's just too powerful, it beats your spell and no roll required. I think though, in the end what players might want is some kind of consistency so they can base their actions on what worked or did not work previously. Which creates a gray area with ad hoc adjudication.
Here's how I see it: The players have no recourse to the rules as they are the domain of the DM to use as he or she pleases to serve the game experience. A player does have recourse to the DM's rulings in the exact or substantially similar fictional situations. So if the DM has ruled that dispel magic will break the succubus' charm, when the players encounter another succubus or perhaps an incubus, then they'd be right to expect dispel magic is going to work. Later in the campaign when they face a vampire, they aren't in the exact or substantially similar fictional situation and thus should not assume dispel magic will work to break its charm. A good thing to do at this point would be to try and recall lore to see if it might work, which may or may not call for an Intelligence ability check, before potentially wasting the spell.