As it stands, there is a practical limit of 511 files/folders that can be saved so any test network would not last long at all.
IIUC a register can hold max 1023 items.
Dunno how much work it is to sort that, probably not a massive amount. I suppose I could look and use the source …
I trust them to make the best call, but I think everyone is in a position to judge pros and cons of any testnet, and express that opinion. Of course everyones judgement does not carry the same value.
I don’t think it’s a duty, but if you’ll even try to spin something up in case of no official testnet, I’ll shout “Hooray!” so loud that you can hear it in Florida!
Unfortunately that’s all I can do, as I’ll be away from keyboard from thursday on. 
Is the BGF still accepting potential projects?
AFAIK, yes.
@BambooGarden would be the best person to ask.