I think the only part that really needs to be examined is the application of GOE to combinations. As for the percentages, right now the bonus for each increment of GOE is
This is not terribly outrageous.
For whatever reason, for combinations the ISU has been adamant about giving GOE only at the rate for the higher of the two jumps, not for both. They have also been firm about not taking the difficulty of a combination into account in base value (4T+3T and 3Lz is harder than 4T and 3Lz+3T, but they count the same). I don't know why the ISU technical committee is so insistent about this; the only guess that I can come up with is that a triple-triple combination is already it's own reward, because it frees up a jumping pass which the skater can fill with an extra triple jump or double Axel. This is already a pretty big reward.