No idea. I haven't finished it yet, but my guess is that Heathcliff is a rather uncultivated, wild individual--a gypsy of sorts; very rough around the edges personality-wise (huge understatement--rather dark and dangerous actually). And Heath works better as a name than Moor I suppose. Certainly the names of the houses, Wuthering Heights and Thrushcross Grange, are symbolic. I suspect Bronte was using his name symbolically also.