The most interesting solution that I've found, and implemented in Rebal, was to make Hard Flux drain while shields are up commensurate with cap. So, there's a real point to taking cap there.
One idea that I'm mulling over for the next public build of Rebal is to make that drain commensurate with the % over base cap, so that small ships can get tuned to take hits and lose Hard Flux, not just big stuff. Right now, the way it's tuned, there's a real point to pushing for full cap on a few of the bigger ships, which feels like a better dynamic to me, but it's not all that useful for smaller stuff. I'll have to test that out soon, as I'm trying to get Rebal's next version done-enough for public comment.