I reckon they should retire number 25 - who was the last decent player to wear it?
It depends on what you class as decent but you might have to go back to Geoff Ainsworth. He last played in 1974 (the year I was born) so I didn't see him play but he played 135 games so he must have been ok.
In the 33 seasons since then, the no.25 has been worn in only 142 of a possible 672 VFL/AFL games. The 11 players to wear it over that time have been:
Jeff Fehring (19 games), Dale Smyth (7), Mark Jackson (31), Stephen Carey (7), Shane Hamilton (27), Darren Steele (18), Tim Allen (1), Jason Snell (13), Leigh Brockman (4), Brent Grgic (13) & Matthew Spencer (2).
Jacko was actually a pretty good player despite being a lunatic. He managed to kick 74 goals in 19 games in his first year at Geelong (1984) and often played a useful role as a Gary Ablett step ladder.
Carey was premiership player at Essendon who was so useless at Geelong that he only lasted half a season.
Hamilton was probably in our best three players in the '89 GF after starting on the bench. In 1988 he kicked 7 goals from a half forward flank against Sydney at the SCG (in only his 3rd game!). Apart from that he was fairly disappointing.
Steele played 118 games with North Melbourne before crossing to Geelong and playing some reasonable footy. Was a fringe player who struggled to cement a spot in an era when Geelong was a very strong side.
Snell was a good player who was probably in career best form when he suffered a shocking ankle injury and never played again - but that was long after he stopped wearing no.25 (he'd swapped to no.4 early in his career).
...as for the rest they aren't even worth commenting on (is Brent Grgic the worst player to ever play more than 10 games for Geelong?)
One more statistic about the no.25:
The last player to score a Brownlow vote wearing no.25 was Darren Steele 14 years ago!! (Round 4, 1993 vs Hawthorn).