JACOB Weitering established himself as the No.1 pick of his draft year by May of 2015, and was never really challenged for top spot. Josh Schache wasn't too far behind, particularly after a record haul of goals in the NAB AFL Under-18 Championships, and deserved his place as that year's No.2 pick.

Every club's recruiting team would have had both in their top handful of prospects and to suggest differently now, as the draft quinella from three years ago struggle to make an impact at AFL level, would be a classic case of revisionism.

Weitering and Schache are but two of a number of young key-position players drafted early in recent years who haven't quite found their place at AFL level yet. They, and others, will be given plenty of time to get there, but clubs are also watching their progress to see if there is anything to be learned the next time a key tall is available at the draft.

"You can't change your thinking based on how other players have gone at AFL level, but it is something to take into account," one recruiter said. "Each case is different. But it does make you do a bit of extra work to see why it hasn't worked for some of them and if the same challenges will be around for the next ones."

Looking at the past five drafts and the talls picked early provides more questions than answers.

In 2013, Tom Boyd was the unanimous first pick but apart from a brilliant finals series in 2016 that helped deliver the Dogs a breakthrough flag, the powerful goalkicker has struggled to have a regular impact on games. He was an emergency for the Dogs on the weekend and hasn't played yet this year.

Paddy McCartin was the Saints' No.1 choice the following year, Peter Wright went at No.8 and Darcy Moore at No.9. Injuries have meant all are yet to establish themselves as the match-winners their clubs hope they will become.

WATCH: Paddy's great start to 2018

From the 2015 crop, Weitering could face a stint in the VFL after his rough trot of form continued last Friday night against Collingwood, while Schache is nursing a calf injury but is still down the pecking order at the Bulldogs after a dismal second season at Brisbane.

Also from that draft, Melbourne's Sam Weideman (pick No.9) and Carlton's Harry McKay (No.10) are still raw and have combined for 12 senior games so far.

Charlie Curnow is the standout from the past five years of talls picked early in the draft, with the emerging Blues star an excellent mix of power, aggression, athleticism and courage.

WATCH: Curnow's round one cracker

The 2016 pool wasn't flush with tall types, although Port Adelaide took Todd Marshall at No.16 and he looks to be an exciting type. He kicked four goals in the opening round of this year and has the agility at ground level.

Of last year's group, key defender Aaron Naughton has impressed so far for the Bulldogs and Darcy Fogarty, in two games, has already shown why clubs could rue allowing him to get through to Adelaide's pick No.12.

WATCH: Fogarty's debut goal

"The ones who have not yet got there have had different reasons. There's been injuries, some haven't coped as well with the demands of the game, some have battled with the athleticism and defensive pressure required of tall forwards, and some need to be more competitive," a recruiter said.

Another view is that the anti-density rules in the TAC Cup – which forces each side to always have at least two forwards and two defenders inside 50 – actually hinders the key forwards' development as it is unrealistic of the challenges they'll face at AFL level with busy forward lines and extra numbers dropping back.

Clubs are aware that drafting talls with early choices is generally a riskier practice than taking ready-to-go midfielders, and that it requires more patience. The game has also moved away from the era of big, strong, bullocking talls holding up an end of the ground.

But with a 2018 draft pool that gets more exciting by the week, and which contains potentially three of the better key position players available in recent years – twins Max and Ben King and Jack Lukosius – will the past dictate the future?

"It shouldn't," said another club. "These guys this year look pretty special. But we have also thought that about other players and they haven't come on as much when in the AFL system. The best tall forwards in the game are either early picks or father-sons, so you just have to get them in when you can."