Yeah, I always hated the salami-slicing effect myself, and I'd come to use fractional hit points long before I finally saw that Sage Advice. YMMV, as multi-classed characters are both too powerful and too weak simultaneously. At early levels of play, their slow development and shabby hit points hold them back from being very useful, but by name level, the fact that they're roughly 1-1.5 levels behind single-classed characters and can be more versatile and survivable can be close to game-breaking (though only close, as it's difficult to employ the advantages of two classes simultaneously). So whether they need a slight buff to hit points or not has a lot to do with the levels you play to and how individual campaigns are conducted.