The setting what was made it bizarre: people from differing social strata working, socialising and dating all in the same building - often in the same room. (I always think of Kate Hamilton finishing at reception and then going on a date ... inches away from where she had just been working!)
There's an interview somewhere with a writer who worked on both Crossroads and Coronation Street who said he could write the same kind of dialogue or story for both shows, but it just inherently made more sense on Corrie simply because of the logical structure of the show - people meet in different places: the pub, the corner shop, a house, the street itself - whereas on Crossroads, 80% of the action took place in this one weirdly artificial environment - an upmarket motel in Birmingham! But yeah, once you buy into (or ignore) the weirdness of the concept then it works on its own terms and yes, the acting is no worse than the other soaps of the period. Certainly, the likes of Sandy and Diane were always totally believable (and often very funny).