I got a WH and a WL, both of them quite high in rr rank and played almost exclusively in solo. WL is indeed a burst beast, not many people can survive the initial damage and react fast to counter it: of course, skill is key here, and you'll find some guys who can turn the situation in their favor. In general, with WL 1 vs 1 and 1 vs 2 are quite easy. Being 100% visibile, you'll be more exposed to zergs and roamers, so you'll need to use maps and terrain at your advantage.
As a WH, you'll have a completely different strategy and approach to your targets, and u indeed can do amazing things with the 100% surprise factor: given the right spec (bal+som+rb), you can kill duos and sometimes bad trios quite easily, or dispatch unsuspecting targets even when they are in mid of some groups: pop out, stun, kill, use ur defensive abilities, declare anathema off a cliff and survive. For me, this is indeed more satisfactory than the pounce-burst-kill WL has to offer. With both, however, you can still do fun stuff, like kill people who are inside the lord's room and get away with it.