I'm finding express super popular at the moment, I'm getting more choosing that than I normally would the week or two before Christmas (which also saw spikes in express being chosen) but I charge for both standard and express. Currently there is an $8+ difference in the cost of my default postage and express, since I use letter post for regular mail, but obviously can only use parcel post for express.

Which is not wholly relevent to much of the points raised in the thread, except the increased popularity of express in current conditions (if being experienced by other sellers) could seriously be a killer for those who wanted to have Plus items but use letter post. 

If eBay will contribute $4 an unlimited number of times for other sellers, perhaps it's not too much to ask them to re-assess their unwillingness to contribute $8 even once for other sellers. (Yar, I can hear the laughing from here  ).