The question should be, with any player, not just Garlett, can they play footy? Understand the concern over behaviour by clubs, but you've got to have some faith in your mentors and structures that you can grow a person. I acknowledge it's a tough decision, but sometimes you've got to put your balls on the line if you want to improve.
All can play footy - its just a matter of what they bring to the club (net value of +'ve less -'ve).
Recruiters don't operate in a vacuum. They are aware of what the head coaches style is like and subconsciously look for players that fit the characteristics. They also prefer footballers that fit the mould of what a footballer is supposed to be and anyone that falls outside these parameters can be discarded/ignored.
As someone with a bit of an idea of what happens in these situations - if a recruiter had a choice in the 1st round between Player A whose ceiling is lower but would give you 150 games at a B+ level or player B who would give you 30 games at an A+ level, 40 games at a B level and 80 games where he's a C at best, said recruiter would pick player A
EVERY time.
Its why all teams passed on Darling in their 1st round picks and despite acknowledging he was a miss, they will almost certainly do the same thing again with a player like Garlett. Its more of a issue for a recruiter to miss a kid who turns out to be a gun, than to pick a dud in the 1st round. 1st rounds picks are just too important to get right.