"What is wrong with the flight deck of the 737NG?"
Seriously unseen. You fly one and you have to ask this question!!!
I can only assume from your post that the 737 is the first and only jet you've flown. Don't get me wrong I like the 737. It's very good at doing what it's designed to do. But it's flight deck is an insult to logic, technology, efficiency, ergonomics and common sense.
For one thing there is no reason for all the systems on the overhead panel to be manual. NASA landed a man on the moon in the 60's and Boeing can't design system logic to automatically control cabin pressurization, fuel balancing, air system configuration and cabin zone temperature control. And don't even get me started on not having a parallel electrical system! WTF!
There's no synoptic displays for systems, even thou the lower DU sits there blank for the entire flight. And some genius decided that if the annunciator light for a system was anywhere near being in the pilots scope of vision, then there was no need to have it activate the "six packs" (glare shield annunciator panel for those that don't speak boeing) as the pilots should see it! really!!!! Not that the "six packs" are much better. They've been installed by the finest low wage Mexican's Boeing could employ, and work about as consistently as James Packer exercises.
There's no secondary flight plan function in the FMC, or alternate flight planning fuction. Because no one has ever needed to know their PNR or alternate requirements before. And I just love having to re enter a cruising level every time I level off because the box is to stupid to realise that's what I've done. Profile managment by the FCC is pretty awesome too. Follow that at your peril.
Your right about one thing thou unseen, It is simple.
If you want to see how a real flight deck should look and you ever have the opportunity strap yourself into an MD-11, I highly recommend it. It's almost like someone took the best aspects of Boeing and Airbus and stuck them together into one super sexy awesome 3 holer machine. The automation and system integration of Airbus, with the conventional control system and pilot awareness/logic of Boeing. And it was designed in the early eighties. McDonald Douglas sure knew how to build a plane, so of course they had to be the aircraft manufacturer to go out of business. Great product, lousy management. Now where have I seen that before!