i think its the fact that the two targets are as far as can possibly be from one another on the map, with no especially interesting gameplay in between them
and then when you actually do get to each one, their positions are so fortified that you have shockingly few options to actually deal with them in the usual hitman ways. i'm not entirely sure there are any "normal" disguises that let you get past the frisk points to the embassy's second floor that the frisking guards won't see through, just the camera man and maybe the intern? and there's no way to the 2nd floor except past those stairs. it just feels really limiting, like your only options are to do one of three opportunities or throw coins like a maniac to get through with a different disguise
the other three are considerably better in my opinion