Bruce Gordon Ti Rock N Road , Fat Chance Mountain Tandem 
Early in my touring career I found that low rider racks limited my off road riding options. The front panniers hit rocks and low growing brush on tracks/trails and rough roads damaging the pannier bottoms and finally breaking the racks. When Bruce Gordon introduced his high Mtn Rack I have happily switched for almost twenty years now.
Your idea mimics much of French and Japanese road touring rack styles that have existed for fifty years or more. This system works very well if you limit yourself to mostly road riding.
Since I work (and live) at a bike shop, I generally have far too much time on my hands, as this next experiment shows. However, I MAY be on to something...
Low rider REAR racks?
Tubus logo + scavenged Boer Yeuh racks
Comments, thoughts, criticism?
Yeah, I've tried this too.
It does improve handling noticeably, especially if you load the heavier, denser items low in the panniers. The bike is somewhat less tipsy and more stable.
If too low, the panniers can scrape the ground during turns.
Sometimes (how often varies greatly from individual to individual) it's nice to have some extra clearance for obstacles and (some) trails.
[Even though there is some degree of improved handling, it isn't a night-and-day sort of thing, and optimizing it too compulsively may not the best way to spend one's time. (Though that would of course depend greatly on you and what you want to be doing with your time....)]