Neale/ Grundy as captain/vice captain cancel out Gawn's value as captain imo.
Preuss is miles ahead of other mid-pricers imo.
Disagree on Preuss being the best mid-pricer for one major factor. He's almost certainly not going to be a keeper. If you think Preuss can be a keeper then your only decision in the rucks is who to start next to him. Realistically, Preuss is a cash cow, he's a 300k rookie.
While I do think Preuss is probably the strongest case guy in the <350k guys to score 95 the fundamental difference is that if Caldwell or Harmes (for example) do that, they're legitimate chances at being keepers. Realistically this goes for all the midprice guys, so Rozee, Taranto, etc. that cost more.
Unless you're strongly against Grundy and Gawn, the ruck keeper level is 120, even if you're against them, it's probably still 110+.
None of this means Preuss is a bad pick but I would say he's a risky one. A 123k rookie averaging 61 matches Preuss making 95. If you think Preuss can comfortably average 95 or you can't find a rookie to do that then he makes a lot of sense. Now this is an oversimplification and I do think one of Preuss big selling points is the potential to score big as evidenced by his 140 which can price spike significantly but he's also got a pretty solid track record of some terrible scores to counter that. He also doesn't have job security until he does, he has no real durability track record to count on (or against) and there is a pretty wide range of outcomes possible for him with the 95 seeming the likely high end of his outcomes.
Looking at rucks changing teams/breaking in to the main role (excluded premiums moving to same role like McEvoy, Mumford the 2nd time, etc):
ROB - 95
Witts - 94
Sinclair - 64
Hickey - 58 & 79
Nankervis - 89
Lycett - 101
Mumford - 92.5
Z. Smith - 77
Phillips - 56
Pittonet - 72
Warnock - 61
OMc - 83
Jacobs - 93
I think that OMc probably deserves a note as he was forward part year, Lycett is an exception as he'd been the top ruck for the Eagles but he's also the best performed.
I'd say Nank, Witts, Mumford and Jacobs are probably the most comparable which would get you ~92, only Witts didn't go to a strong midfield in that group (Ablett aside) so don't think the GWS factor changes anything. Pittonet, Smith, Hickey and Warnock probably represent the worst case scenarios, for the most part they all failed to asset themselves and ended up in ruck battles.
Ultimately, Preuss should, imo, be assessed against rookies at other positions. If you can find a rookie at 123k with moderate job security and a decent chance to average 60, you should take them over Preuss, imo.
For mine, I still think Marshall at R2 is the better play for those fading Gawn and pick a rookie over Preuss on another line or another midpricer who has premium potential.