A bit of constructive criticism helps counterbalance the unbridled adulation displayed by many posters. Sier is a welcome surprise of a player - I never expected him to play AFL, so my expectations of him were minimal, and easily met by the winning form, skills and physique he displayed in his 12 games.Needs to build up his tank over the next couple of years for that to happen - still only good for shorter bursts in the middle after the initial heat has gone out of the game a bit at the moment (although I'd expect some improvement on that this year) and his movement and positioning off the ball needs a bit of work too.
I have viewed his 14 minute 2018 highlights video at least 5 times, probably more, and experienced semi-orgasmic pleasure at his looping handballs to running players, his slickly flicked handballs under pressure that open up a running offensive, or a kick into a forward expertly tailored to the strengths of that player. I was devastated at the thought he might miss the grand final through injury. I cannot get enough of Sier.
But of course you are right about tanks and heat and that sort of thing, though I think he is a better reader and positioner than you allow for here. 2019 will be the Year of the Bear.