There is no need to change mortality rate. Combat logging is a separate issue and has nothing to do with balancing as it is cheating.
Have you ever mined or explored? Because you sound a bit single-minded.
I have used core mining extensively, and posted detailed research about it on this forum and others. I have a mining challenger build with 2700 HP that would kill a weak ganker and escape from the rest of them, and with it I've made hundreds of millions of credits (like everyone else with their aspX or whatever). Trying to squeeze a mining build onto a challenger taught me exactly how many modules are needed. I can provide links to build or research notes if you don't believe me.
If I can make a challenger mine & murder, you can make a conda or a python mine and explore and mechanic without being paper thin.
And yes, I had to make sacrifices on that chally, it has fewer collectors than I'd like due to its mil slots. Asp/python/etc is faster for this reason. The sacrifice makes gameplay slower, much like lower jump range on an explorer. But it won't die to some gank.
If you want a small/medium ship besides the python (and maybe krait) that can do three things then you are really asking a lot, since no one else gets that.
I never did the old mining, because it was not fun for me. With the new mining, I actually get to fly around and aim a bit, and also make ridiculous amounts of credits.
No, I haven't done exploring in the way you mean it, just various prospecting/barnacles/grind unlocks, etc. It's not enjoyable for me, but that doesn't invalidate my view that a ship in open should be able to survive in open.