One daily certainly doesn't do justice to the potential on those routes. HAJ-MAN was operated up to 3daily by BACon, and then 7/7 BE + 5/7 X3 with 737-700/800 - seeing about double the current pax level in 2006, 2007 and 2008. On a E175 (rather than X3's 737) there should clearly be the potential for going 12/7.
Surely high loads on this route were related to VFR traffic for people serving in the UK Armed Forces in Germany? Since then of course there has been a massive draw-down in our forces and presumably therefore demand on this route.