Maybe EBU prizes should be less flexible? e.g. have to be used in the three months following the event, or have to be used at one of a list of events. Might encourage people to play events that they otherwise wouldn't, and would allow bigger prizes/more prizes due to the likelihood of some prizes not being cashed.
"More prizes" helps in terms of formats, too - it makes it easier to be able to afford a reasonable prize for "2nd in group C" or "best ascenders'" or "best pair ranked below an ace on NGS".