I guess based on the fact he lasted till 19 tells you at least quite a number of clubs had other players ahead of him.
I do recall he was injured for a decent part of last year including the last half i think, which may have had some effect.
Also i think clubs are choosing based on player type to assess their value to their team more and more these days, even early in the draft. They just don't want to admit it as it might lead to them missing out on the player.
Looking at some of the others who went before Stocker, we wouldn't need someone like Ben King who went at #6 because we have Charlie Curnow/McKay/McGovern up front and Weitering/Jones/Marchbank/Plowman down back. Using a high draft pick on ANOTHER KPP would have been dumb.
However a lot of clubs would need a KPP like him and maybe therefore have him higher on their draft board.
IIRC Rozee wasn't predicted to go quite as high as #5 for most of the year, but Port needed a player type like him and he was from SA, boosting his rating to Port in particular. Obviously been a good pick up. They also took Butters & Duursma, outside types with run and some x-factor to compliment their inside players like Rockliff/Wines/Powell-Pepper/Boak. So for them they wouldn't need someone like Stocker and neither would Adelaide with your abundance of big bodied, inside mids etc.
Just because he went at 19 doesn’t mean he wasn’t at 12 on numerous lists. Future trading has inherent risk plus you need a few other factors to line up to do it. Even though SOS had him at 6, you don’t see the live trade start gearing up until he’s slipped about 10 spots. Then the metrics need to be reasonable and risk assessed. The likelihood of 2 clubs being comfortable with the factors when the player has slipped 5-6 players is unlikely. When it gets to 10+ the other party shares in the perceived benefit. We didn’t pull the trigger at 16 and nor did Port a couple later. Looking from the other side, if Port did the deal, we win the flag and you win the spoon, McHenry will want to be one hell of a player for us to not look like idiots.