I have zero complaints with W necks. I have 3 (1 Wolfgang, 2 Standard Thins). All are roasted maple shafts with SS frets, with 1 having an ebony board and also being a 24.75" Tiltback Strat.
Maybe my mindset is different in that all 3 of these necks were used on builds starting from unfinished bodies. I expected to be doing some very fine sanding on the back and fine tuning the frets. While I found all 3 very playable before doing anything, the work I did made them better.....lower action with very polished frets and butter smooth on the back of the neck..... effortless playing.
I would assume if you're working with a custom builder, then yes, I'd expect exceptional fret work and a perfect drop in neck for the instrument.
However, I've always seen the Fender based bolt on's as a starting point. Great instruments that can really shine with some TLC. While I haven't played a zillion examples, any sample I've bought or played in a store have had neck work on par with W's in terms of fret work. In both cases, very playable out of the box, but with some TLC become really good. I'm totally good with that, and all 3 W necks I've sampled were very good out of the box.