Prince Henry - I think you'll find the guys who decided to drop back to lower grades were always going to do so in 2015 regardless of the coaching staff. Donno, Ferg etc have each played 200+ games for the club and it was taking its toll, especially considering they were blokes playing for the love of rugby, not trying to go pro.
What was more concerning was the blokes who didn't even play at all this year such as Ellis, McWhirter, Zangari and Zonka to name a few. Granted a few of them had increased work commitments but its still hard to build a strong Premier/Premier Reserve team when a bunch of cornerstones leave.
Goodluck to the three GPS teams in finals this weekend, Prem Colts, 3rd Grade and 4th Grade. I'm sure they will all give it a good crack.