I'm not guaranteeing anything in the draft, there will always be risk in every decision made in terms of list management. Whether you trade or draft, there are equal amounts of risk except the majority of supporters know the traded players name and what he plays like.
That doesn't mean the club is taking any less risk, they will have a strong idea of the strengths, weaknesses, abilities, development etc of the top kids they draft too. The difference being they may take a couple of years to realise that potential but they'll have a far longer career and output. Conversely, a traded in player has a limited time to have an impact and may have played their best footy in the past.
Having touted a rebuild a few years ago and turfed so many players with something to offer in order to do it, the club didn't hit the draft hard. They picked up a bunch of players who were older in order to make a quick return to finals which hasn't panned out. Now those players are older again with even less time left to impact the club and without the development of youth driving a push up the ladder, the side looks stagnant. If we continue to top up with mature players, we're likely to continue to sit mid table and irrelevant.
Bringing in Kelly (and Acres or whatever other mature player) will be another kick in the teeth to that and extend our stay without a premiership. If Kelly was coming at a great price then I'd be happy to grab him but he won't be. If he cost us a pick in the late teens then I'd be happy to consider it but it looks like we're about to get bent over. What do you think a good deal for him is? We traded pick 23 for B Hill who was 23 at the time and a 3x premiership player for reference.
Your recollection of things is a bit off Raglan, Darcy went to us in the second round and was the second ruckman chosen behind Tim English. He was the dominant ruckman in his draft year winning hit outs at will (although English was drafted first because of his athleticism) and went in the second round to Freo who were searching for a Sandi replacement. Late second to third round was his expected draft range.
My work requires a lot of referencing and substance to any argument made. If you don't have data to back it up, no one cares what you have to say!