My biggest concern would be it going anaerobic over time. I'm thinking that if I try this I would only use large wood, closely packed, in the hole, and then top it with a layer of peat moss to keep soil from migrating down.
It would cut out the liner, etc. which is not cheap, especially if you actually want it to do a good job. And it would be more self healing then a plastic liner.
We have fairly heavy clay subsoils on our place. When I built some of my beds I intentionally tapped into that layer with vertically placed logs with the intent of increasing that wicking action from that layer into the upper reaches of the mound. It seems to work pretty well, as those areas appear to retain more moisture...so I think it is a worthwhile experiment to take on. My next beds will have the entire center section construction this way.