After reading the thread you linked to (which is about the Behringer XR-18, not about Mackie mixers), I just want to understand what you mean: are you saying that one shouldn't rely on wifi at all, or are you saying that built-in wifi solutions are more prone to connection drops and other mess-ups than separate wifi routers connected via LAN cable?
I've been using iPads with my DL32R for years now with varying audiences, large and small, never had an issue with losing connections. I've been using an Apple Airport Extreme as my main access point, with an ASUS router as backup, both stable with no issues.
Yes, I'm looking forward to MasterFader 5.1, when I can actually run it on a Microsoft Surface and connect it directly via LAN cable in cases of severe wifi congestion, but I haven't yet encountered major issues with wifi dropping with my setup.
But if you have some specific facts on the built-in wifi port on the DL16S/DL32S and why it could be problematic compared to a separate wifi access point, I'm all ears.
Cheers,
Torsten