Dare I suggest Conti MK Pro 2.4s?? OK maybe not 🙂 I've been running these for over a year on my 5 in The Peaks and they've been more than fine for most conditions.
True, they are not the grippiest of tyres but are light, tough, hard wearing and more importantly roll really quickly.
I've had Maxxis Advantage 2.25s on the 5 before this. They were OK but in my opinion not as good as the Contis. I also tried a Kenda BG 2.35 DTC front and Nevegal 2.35 DTC rear. As you've stated, found them to be too grippy and very draggy and removed after 2 weeks.
Currently considering Maxxis HR front and Larsen TT rear, WTB Wierwolfs, Schwalbe Fat Alberts or Nobby Nics.