My Mk2 and Mk3 5 string Wals had beautiful necks. Slim, fast and perfect. The weight of the Mk2 was the only downside. The Mk3 had no downsides at all, but anyone willing to spend upwards of £4500 on a bass had better have played a lot of them and decided that nothing else will do.
You do not want to find, when you've spent that kind of money and waited 3 years, that you don't like the neck profile. Or anything else about it!!
My Mk2 was replaced by the Mk3 and that was replaced by my US Lakland. I have no regrets about any of those upgrades.