Betts is clearly the best small forward at this point. The Sloane and Laird selections can be fairly easily justified.
Talia is probably doing as well as any KPD, but is not a massive stand out.
Walker selection is probably showing Crows bias. Walker is 5th in terms of goals kicked by KPFs. He has the best accuracy and is 3rd in terms of average goals per game by KPFs.
Of course the role of forward is slightly broader than merely goals kicked. If you are rating Walker in that manner, or any KPF for that matter, then you are probably doing him a disservice.
A number of KPF are having great seasons and each one goes about it in a different manner. Using SC points as a proxy for output - not ideal but sufficient for this purpose - we end up with the following ranking.
1. N Riewoldt 121 pts
2. Walker 114.7 pts
3. Kennedy 108.0 pts
4. Hawkins 101.0 pts
5. Lynch 99.8 pts
6. Cameron 96.0 pts
7. Franklin 94.8 pts
With the distinction between FF and CHF less than it has ever been, selectors are ultimately tasked with picking two or three of these players. The biggest argument against Walker in a rolling AA team right now is that he has only played three games, which in this scenario means that he has missed one-quarter of the season. But based purely on average output he is more than deserving of a place in anyone's rolling AA and including him in no way constitutes Crows bias.