Firstly I should say that I rate Bourke quite highly, especially in comparison to some others around here. I think the reasons that Geelong and Gold Coast didn't take him are 1) they have young KPP, 2) they rate their KPP more highly, and 3) they didn't have the list space. Clubs seem more weary of taking a middle of the range father-son prospect these days as they like to have the ability to trade their second and third round picks, Geelong probably also wanted to retain the ability to trade these picks so didn't pick him up. Look at James Stewart this year (probably more a third round onwards talent), and Tom Curran this year (went second round overlooked by the Hawks), clubs seem to no longer automatically pick up talented father-sons who are not first round quality.
I do rate Bourke highly, as a late second rounder, he has good athleticism for a forward, he is a pretty good mark both on the lead and in contested situations, he is smart knows where to lead, he can play decently down back (probably not in the midfield), he also has a good skill set. The downsides are that he has average hands below his knees for mine, nothing special can fumble, he has no real defensive side to his game as a forward, he is quite skinny so long term project who may not make it, he hasn't really dominated much, but had a decent game at the champs, also his endurance needs improving as does his workrate imo. Still there is a lot to work with, I would take him with any pick we have after 33 (not 333, 14 or 8) or more likely in the rookie draft.