The predominant issue they need to fix is the "search" function..
Try this experiment -
Pick an item.. search in "All" on ending soonest , take note of how many items appear, now do a specific category search from the list at the side, you will see that far MORE items appear.. I tried this several times different items same results..so many items do not appear at ALL, when searching "all".
Others have noticed this same thing, just one other thing thats wrong with the search..
Also after speaking to a few people the following is happening.
If you do a search for any item, again in "all" and price+postage lowest, this would applies to items that have pages of results, the results appear in order as follows -
Featured Listings
Buy it now
Regular Auctions + postage
Regular items no postage specified IE: Pickup and or postage in the body of the listing.
Now ..because of the order in which they appear, Much cheaper items can appear way after (even pages later) than the initial expensive items have been reached on the list, because of this many many buyers scroll down and see their price point reached and go no further thinking that everything after that point will cost more because they searched via "Cheapest to most expensive".
The result of this is that a HUGE amount of Sellers never get a buyer looking at their items, period.