I agree with you on the point of them understanding each other. If anything, Kaladin notices this internally when he realizes that her life was not as easy as he thought it was originally. If anything, Shallan's struggle is more internal than Kaladin's (but you can debate this forever). Also, the fact that both of them are Radiants will probably add to it, and since "Oathbringer" is going to be Dalinar's book, I'm sure Adolin will receive some attention so this love triangle will have plenty of time to play out. I, for one, am hoping Adolin goes Darkside though, but that's just me XD R.I.P. Sadeas, he had it coming though.