This won't be a major issue. It's very common for items to be consolidated and shipped to warehouses. Like with anything, there most likely would be a size/weight limit for a single box. You'd also have to package everything you're shipping prior to consolidating it into a box. People have been doing this for years with various shipping services without issue, in fact with Amazon FBA unless items require some sort of prep (like a glass mug), items are just sent in loose. What most people here are suggesting is that items are protected and prepackaged ready for individual shipment, and then placed into a batch together in one box. Ala Chit Chats.
eBay would need a system where a unique label meant to assist with their hub's sorting process would be added to each individual order, and then possibly a batch label to the outside of the box. Something as simple as individual barcodes for each order might work. But that shouldn't be a major hurdle.
Then I assume eBay would simply apply the carriers label over the packaging, just as they would do if you sent the item in individually.
Based on current shipping rates, it makes too much sense to allow consolidation of packages. Let's say over a weekend I sell 20 jerseys that weigh about 1 KG in poly bags. Those are going to cost me about $12 each to ship to eBay's hub using Canada Post or UPS with eBay's discounted rates. That is $240 dollars. I could ship those consolidated into one single box for $25-$30 at most. Assuming each order is worth $100 on average, add in $66 in optional insurance at the Canada Post rate of $2.75 per $100. Let's assuming $5-$10 wholesale for a box large enough to hold 24 poly bags and rated for the appropriate weight, we'll call it $100 to ship consolidated with full insurance and safely packed.
If you're sending two shipments like that a week, that's over $800 a month in additional revenue that you can either add to your bottom line or use to lower your item costs. Savings may increase or decrease depending on the size of the items, whether they qualify for Expedited Lite, the amount of total insurance needed on the consolidated box, and where the seller is located relative to the hub.
It would be a very efficient feature. Nobody wants to hear this part, but eBay could probably charge sellers a $1-$2 "sorting fee" per item and it still might be a cost saver for some.
