In terms of output, all bar Sheds are past their peak in my uninformed keyboard opinion.
I think we now get C-level output from Jack, B-level from Cotch and Bachar, and A-level from Sheds.
Arguably Jack's career is being extended by the presence of Tom Lynch. They compliment each other well and Jack is able to benefit from Tom's heavy lifting. Jack is still contributing adequately. Personally it was the decision not to operate on his knee in early 2019 that will impact his final years the most. However it did get him a 2019 medal and therefore paid off.
I am expecting it is Bachar's last year, Jack 1-2 years, Cotch 2 years and Sheds 3+ years.
No disrespect to Bachar, but I think he is the easiest to replace and Short/Baker to some extent have already stepped up and filled the gap. Bachar is an elite distributor which Short/Baker are very good at, although not elite. It is clear Bachar will be around the club for many years to come through his foundation work.