So much this!
I've recently seen a board go from mem CBB at -10 (on three different kits) to easy full pot (on two of the same kits) just after digging an impact-reset-button-sized amount of dirt from what looked like clean RAM slots at first.
How do you know/prove if someone else gets a current-gen ES by "pure luck" or by having a direct job responsibility?
You have to draw a strict line somewhere and not allowing current-gen ES outside the Elite league is the solution that makes most sense.
Everybody can get points from ES as long as it's not current-gen. If it's current gen and you want points - move to Elite league. Where is the problem exactly?
I would actually agree that this (and the P5E64-WS Evo) is the best all-around 775 board: it supports all existing 775 CPUs (except for 130nm) and can be properly efficient thanks to non-crippled DDR3 clocks.
P45 boards are indeed better for raw FSB clocks, but they usually have poor efficiency.
MNH-E was the first revision that had sudden death issues which caused the sticks to die on random after a couple of months of use. I'm not sure if this is still relevant because if sticks were to randomly die, 6 years was more than enough time for them to do so
Other than this, I'm not sure if you'll be able to spot any noticeable difference between MNH-E and MGH-E.
All Hynix kits with specs of 2800C14, 3000C15, 3200C16 or lower are pretty similar in terms of average quality. If you want something better, you'd have to go for 2666C13 Kingstons (as suggested) or expensive 3200C15/3200+C16 kits.