bigbuck:
Your question is dead-on. Regardless of what method you use (direct dialing like us, chart dialing MOA, reticle holdover, etc) it's important to know where your bullet is going for that particular shot.
With our method, the easiest way to account for that is with a drop compensating turret that matches the conditions you are hunting in. Generally, you get 2000'-3000' and 20deg on either side of what your turret is set at before you can see enough impact variance to effect hunting accuracy when using flat calibers and high BC bullets. The actual range, shot conditions & individual ballistic performance can shrink or enlarge that window. Swapping turret dials before a hunt is very easy and requires no rezeroing.
If you are in a situation where your dial isn't a match for the conditions you are in, it's important to know what your bullet performance is for whatever conditions you face. If an extreme incline, big temp swing, or big altitude change is an issue, the shooter needs to now how to adjust for that. Making that adjustment is no more complicated with a direct dial system than it is with any other system.
The advantage to a direct dial system is that for about 80% or 90% of the shots we encounter, we can just dial and shoot if the dial we have on is a basic match for the conditions. You can cover a good chunk of the remaining shots with a basic understanding of your rifles performance and some simple "rule of thumb" adjustments.
For the occasional shot that requires some heavier calculating and maybe a chart reference, a direct dial system doesn't have anything stopping manual adjustments.