The only way The Force makes sense to me is as an adaptable trait present in all creatures, like empathy.
Empathy, in its truest form, is instinctual perception. Every animal is instinctually capable of interpreting body language and non-verbal cues from other animals, that's how they communicate almost silently. Some animals are more social and by extension better at it than others, but all animals are capable of this action, including humans.
Where humans differ with animals in this regard is the degree to which they can exploit it when they are skilled and/or talented at it. Just like math or art, anyone can learn to be empathic and instinctually read creatures' nonverbal cues, but some people naturally excel at it. Those who naturally excel at it often experience moments in their life when people look at them funny because they will say or do something that shouldn't make sense unless they had some knowledge they didn't have (I'm talking natural everyday occurrences, not paid psychics).
With refinement skilled empaths can take their talents to seemingly supernatural levels, but that skill isn't beyond anyone. In fact it is quite common for dedicated monks, especially of meditative disciplines, to be adept at sensing a great deal about someone just by looking at them.
This probably sounds like a useful skill much like basic force levitation right? Well it is. But you also don't see everyone dedicating hours of study every day to develop such skills. Why? Well mostly because people think it's 'hokey' or nonsense, much in the manner of Han Solo. Greater empathy also brings with it a level of responsibility because you begin feeling what others feel more deeply and it becomes harder to accept and deal with everyday common cruelties (there's more than one reason monks live in seclusion).
Translate this to force powers and it neatly explains every facet of the force in established canon (both with and without the EU). Not to mention it jives with the 'flavor' of the force far better than something as asinine as midichlorines or genetics.
People have children with personalities and skills similar to their own, so a couple who's adept at understanding and manipulating the force will have children who are naturally inclined to understand and manipulate the force.
Animals are capable of basic force skills, but only the ones who've developed an instinctual understanding of that facet of the force for survival.
Every person is capable of developing force skills, but only a few are either brave, disciplined, or instinctually inclined enough to do it (hello punishingly-demanding-Jedi-training).
Sith who've never had Jedi training, like poker grifters, learned to use their skills for self-gain, on their own, without a code of morality to guide their greater understanding of life. Genetics or midichlorines would provide no method of understanding how to use force 'abilities' without instinct, and as I've spent this whole post explaining, instinct renders all this predestination genetics/midichlorine nonsense moot and unnecessary.
Finally, both midichlorines and genetics fly in the face of 'The Force'. The force has always been described as something that binds the whole universe together, a kind of shared omnipresence between organisms, not a super power lottery. Reducing the force to a simple gene or physical characteristic destroys its spiritual significance and by extension the entire presence of the Jedi/Sith orders. I mean the Star Wars universe already has the capability to clone an entire army in half a human lifespan. If the force were as easy to understand as genetics or midichlorines in a universe like that, you'd better believe someone would have already made and mass marketed 'force pills' or something to give everyone super powers.
Anyway, I don't hold the reigns on the franchise, and predestination is all the rage now, but I wanted to get this out into the aether. I don't know if anyone else holds a similar view on 'the force' or if everyone totally digs the predestination schtick, but for my part I always have to plug in the above to any given Star Wars story or the force just doesn't make any sense to me whatsoever.