Honestly, I'm not fond of multi-classing in 5E. The Multi-Class feats that WoTC have come up with so far, and ENWORLD's Multi-Class feats, are probably the best way of 5E to do any kind of "Multiclassing" since there is a bigger focus on Single Class and Capstones. (regardless of how crappy some of said Capstones can be.) I do hope we get more (and more) multiclass feats from WoTC or wherever.
But, the buff to CHA casters that happened this edition aside, I think the Hexblade is a nice choice for em due to the dip. MAD sucks, even if its supposed to be a kind of "balance" that is intended. And even if I wanted to play as a Paladin, that SAD is incredibly tempting.
Course, I blame that more on the fact that a Paladin/Warlock or Paladin/Sorc combo strangely seems to make a better Paladin than................the actual Paladin itself.