When canopies are too-lightly loaded, they take forever to open and easily collapse in turbulence.
The flip side of that debate is that you will be descending so slowly that you will probably not notice a collapsed end cell on a lightly-loaded canopy (less than 0.6 pounds per square foot).
Keep in mind that minimum wing-loadings vary with canopy model. ... 0.6 pounds per square foot may be the minimum wing-loading for a student canopy. OTOH that would be ridiculously-light loading for a Velocity which is designed to be loaded at 2 to 4 pounds per square foot.
BASE jumpers commonly expect their canopies to be loaded very, very lightly. But they jump 7-cells with low aspect ratios (i.e. how tall the cells are as compared with the width). Lots of room for the air to rush in.
You can end up going backwards in lower winds than other people; of course, you'll still be way better than people used to be jumping rounds 40 years ago. Trust me on this -- I jumped rounds for a long time, as well as more than one low aspect ratio 7-cells loaded at under .7.
When you load in the .3 (or lower) range the canopy actually stops functioning as an air foil, there simply isn't enough weight to create enough airflow. Pulling the toggles may give a minor amount of heading control, but for all practical purposes you're under a funny shaped round.
"big tall cells" is pronounced as "finesse ratio" by aeronautical engineers. Finesse ratio defines the height of the airfoil (rib) compared with the chord. IOW "How fat are the ribs?"
Thin ribs are only found in fast canopies, like Velocities. Since they go so fast, they are deflecting lots of air and only have to deflect all that air by a little bit to generate enough lift for landing. Canopy piloting competitors (aka. pond swoopers) routinely load their canopies at more than 2 pounds per square foot.
Medium thickness ribs are sewn into most mid-range canopies: student, tandem, sport mains, reserves, BASE and canopy formations.
Thick ribs are reserved for slow canopies. They need to deflect - what little - air a lot to generate enough lift for survivable landings. Remember that classic accuracy competition (precision landing) can involve stalling the canopy onto the target from as high as 30 feet (10 metres). When they are stalled, square canopies fly like small, awkward round canopies. The only way your ankles will survive classic accuracy landings is if you have LOTS of fabric overhead, say loading at 0.7 pounds per square foot.