Obese featherweights in my opinion. Middleweights are nicely spaced weight-wise between feathers and heavies, good if you want something bigger but not as heavy as 100kg. To me, lightweights are one weight-class too many. Either go slightly smaller and build a feather or slightly larger and build a middle (ignoring the fact that middles currently aren't popular)
I guess you could apply the above reasoning to almost every weight class, but the LW category just seems unnecessary.