Incenjucar
Legend
NOT running a ton of encounters that are just traps with no monsters and skill challenges that eat surges is extra work?
Having to actively avoid starting the day off with an epic trap room can be extra work, yes. Having to add vampire food to the game to make sure that one of the characters won't drag the rest of the party down can be extra work, yes. Having to make sure that I never start an adventuring day with a skill challenge or monsters that drag in surges can be extra work, yes. It limits my freedom as a DM in ways that no other class does, not even Knight and its horrible lack of function around anything with a good push power.
Then again, a player should also know what kind of campaign they are getting into. A slayer would also do poorly in that campaign, as unlike a number of other strikers he doesn't get a bunch of skills, and utility powers, that would be useful in all these trap/skill challenge encounters.
You can break most traps with damage. Slayers do fine against traps. Skill challenges simply utilize skills most of the time, and while I don't have that book, I'm willing to bet that slayers have access to skills roughly on-par with the fighter. Athletics, acrobatics, and endurance are all extremely useful in many skill challenges.
A vampire is something that isn't just about to pop up anywhere. I did say a player can play a drow vampire in my Dark Sun campaign if he really wants to, but he has to be named Ash. As in Pile of.
That's your bias. At worst, I tend to allow just about anything if someone's willing to reflavor it.
Regardless, a DM should at least know what his party is like AND a player should know what the DM and/or campaign world is like. A Charisma based Paladin may be solid in an expected fight, but when he finds out the party is spending most of it's time fighting at sea, the "no strength, no athletics, plate armor and heavy shield" suddenly doesn't seem like such a good idea. [The vampire, on the other hand, doen't care if he sinks to the bottom of the ocean, he can't suffocate].
While heavy armor is not the best in a nautical setting, it's incredibly easy to overcome. Worst case scenario, give the paladin a floating shield ASAP.