I've had both models, and the NT version neck dive is actually worse than the BO.
The body shape is slightly smaller on the NT, resulting in worse dive, and it's just the way that bass is.
It sounds AMAZING, but there's a price to pay for it with poor ergonomics.
I've seen all sorts of "solutions" from ridiculously extended strap buttons, to adding weight to the bridge end of the bass, but at the end of the day it's never going to balance well.
Even the most famous Thumb player, Ryan Martinie, moved on from them and now has a Fodera with the same pickup placement. It doesn't sound exactly the same, but it's close enough, and likely WAY more fun, and easier to play.
I'm not saying buy that Fodera model at all though. If you're seriously looking for that Thumb sound, get a custom bass from your choice of luthier. You can get the pickup placement you want, a good EQ, and better ergonomics for less than a new Thumb (because new Warwicks are EXPENSIVE).
Thumbs look cool, sound amazing, but are absolutely horrible to play. Check out a Streamer Stage 2 if you've got the cash. It's a different kind of punchy, but I didn't miss my Thumb at all after I got my (used) Streamer. Or get something custom for less than a new Warwick.