In a way perhaps it kept her as an idealised image of love and home and comfort for us, probably as Ben and Jake would remember her. Probably that's not what the writers meant to do - I'm guessing they never came up with a good enough story to tell and it just wasn't interesting to them - but I think the effect is one of idealisation, memory, loss, a sense of stability and warmth that was unrecoverable to Ben or Jake and therefore not something that could be revisited at this point in their lives.
Having said that I did feel the Mirror Universe did a decent job of playing around with the issue of the lingering feelings towards Jeninfer.