Thoughtseize suggests you should just say "You choose a creature card and a land card from them." instead of this and/or nonsense. Players will always take both anyway, and this way players can force the discard of a dredge card or something.
Pretty sure this should have a drawback of some life though.
I disagree. I think it's almost perfect as is, because the person can just reveal all noncreatures/nonlands, if their hand is capable of it. The omly mod I'd make is to make it target opponent, instead of player.