Well, it depends on whether the AFL think that 4/4 home prelim final losses will count as sufficient evidence that a trend has developed. I think its far too early irrespective of whether GWS and Geelong both win to say conclusively that the bye has a truly detrimental effect, but given the AFL's reactionary nature they will likely change it if those results do occur. It may lead to both these premierships in the future being marked with asterisks or seen as not as worthy as others due to the change in format being considered to handicap the best sides.
I think it depends on if the upsets occur because:
- The side coming in from the semi's played up to their potential because they'd had a break before finals
OR:
- The side hosting the prelim struggled due to too much time off
Last year the Dogs played very well in the Prelim and weren't tired after 2 big finals in 2 weeks because they were fresh heading in to September. The Giants also played well in the Prelim and the game went down to the wire. The Dogs benefited, the Giants weren't prevented from playing well.
The Cats were very flat to start the other Prelim and were beaten around the ball early by the Swans. But the Swans had done that consistently to Geelong in recent history, and did it again down at Kardinia this year. Most people thought they were going to do it again last week before Scott made some big changes to the game plan. The Swans struggled against the Giants then played (reasonably) well in the next 3 finals. The Cats struggled in the Prelim but that's just one team.
Adelaide and Richmond losing by playing poorly will be a knock on the bye, but if it's a case of Geelong and GWS winning by playing well then that should be a support for the bye. The home team seemed to win all the time in the Prelims pre bye.