If so, Paladin is harder to...what? Get the minimum stats needed?
Not in BG1 or 2, because you pick the class before stats are rolled. Any stat that didn't roll high enough to meet the minimum is automatically pushed up to the minimum, so rolling a Paladin in BG means you have 100% of getting a 17+ CHA.
Actually, not in any other AD&D CRPG that I am aware of; you always choose your class first, then you roll stats.
This is in contrast to games like Wizardry and Might and Magic, where you roll stats and *then* choose a class based on your stats, but you can always reroll until you get the class you want (though it can be annoying to do so in Wizardry, particularly if you want a Samurai).
Of course, Bard's Tale took the approach of not requiring minimum stats (as did D&D 3e, but full casters have de facto minimum stats; you can make a wizard with 9 Intelligence, but she won't be able to cast spells, which defeats the point), while Wizardry 8 allows you to choose a race/class combination that doesn't have enough stats; the game just forces your level-up stat points to go toward the stats whose minimum requirements you don't meet.
Since all rolls which don't qualify for the class are automatically dismissed and not shown it's easier to get a good roll for a class with high stat requirements like paladin than for a fighter.
Correct, but at the same time, all the more difficult it gets to get "Perfect roll" for such a class (by perfect here i mean enough points to max all attributes and leave a dump stat; also, paladin's intelligence is the dump stat and its minimum is above 3, plus he needs it around 6 so as to not die immediately by a certain enemy in BG2). Once or twice though i did get a roll for a paladin, enough to max all stats and have intelligence at 6 or over...
Actually, I don't think BG2 Paladins (or Paladins in any AD&D 1e/2e based game) benefit from high Wisdom, so you could set that stat to minimum without any problems.
(Also, don't forget that there are potions that can increase Intelligence temporarily, and that may be enough to get past that certain enemy type.)