I really don't consider the K702 to be lacking in bass; with a good amp it has plenty of bass extension and presence, but you just don't have the bloated midbass that you get with a lot of other phones. Its an overall "leaner" sound, but it isn't at all tinny or weak to me. You don't get quite the fullness or musicality of other headphones with more peaky bass, but you get a ton of detail and treble energy, and that is what I like about them. You can still hear bass instruments and nothing is ever so recessed that you can't hear it (in the bass region); it is more of a tonal change.
An E07K will do fine with the K702s. Mine broke so I bought an O2 amp and it seems to do even better, but I can't A/B test it until I get the E07K repaired (which will take a while since I have to ship it to china...).