TL;DR
To increase Cargo Landing Pad throughput, which can often feel like an artificial and boring limitation on production, I suggest that we add a new building, the Loading Bay, or increase Cargo Landing Pad size via Quality.The Problem
The amount of items you can remove from a Cargo Landing Pad with inserters is very limited, even with Legendary Stack Inserters. You can use massive swarms of logistics bots to help, but this is 1) not UPS efficient 2) still limited throughput 3) not an interesting solution 4) limiting on player options. Also, the problem can feel 'immersion breaking' or 'artificial' as it has limited grounding in the gameworld - players can feel like there's insufficient reason for why the Engineer could not build multiple landing pads to solve the problem.Problems with other solutions
Some solutions obviously create worse problems than they solve. I will quickly go over them to explain why they're not the solution I suggest.Removing Landing Pad Limit
This would immediately trivialize onworld logistics as you could just drop any resource anywhere you would want. There would be one uncontested optimal logistics system, which is uninteresting.
Allowing items to be removed from Cargo Bays
This would allow players to instantly transport items across infinite distances, also trivializing onworld logistics and becoming uninteresting, plus item teleportation like this feels unrealistic.
Solutions
The Loading BayThe Loading Bay would be a new building, unlocked alongside the Cargo Bay. It would have to be placed directly connected to the Cargo Landing Pad, similar to the Cargo Bay. A group of Cargo Bays could potentially be connected to a Loading Bay or remain needing to be connected to the Cargo Landing Pad. The Loading Bay would be similar to the Cargo Bay, but you would be able to use Inserters to remove items from it. This would (with a hypothetical 4x4 Loading Bay size) double the amount of space that inserters could interact with to remove items, doubling Cargo Landing Pad throughput.
Quality affecting Landing Pad Size
An alternative way to change the amount of space that inserters can access from the Landing Pad would be to have quality affect the size of the Landing Pad itself. Scaling could be arbitrarily determined by how much throughput would be a reasonable/balanced number, but for example adding 1 tile in each direction per quality tier, would have a Legendary Landing Pad maxing out at 18x18, or about 2x current throughput. This is nice because it avoids adding another building with a limited use, but perhaps runs into problems with sprite scaling.