He did inherit a poor list but if anything it's not as bad as our results have been during his reign.
I must say as an outsider, this year I completely disagree.
Player for player in terms of current output how many lists are the bulldogs better than? I'm not talking about potential future output (Stringer, Hrovat, etc) or past performance (Morris, Cooney, Boyd, etc) but right now what they can put on the field. I'd say you're definitely in the bottom 3 and arguably below Melbourne whose youngsters are more advanced and have a few more solid to good players in their prime (Clark, Dawes, Jones, Frawley, Garland). Of course Melbourne, for whatever reasons (coaching, culture, etc) are getting nowhere near the best out of their players. In my opinion your results this year have been over and above what I would have expected given the players current playing level.
Take the StKilda game. I think player for player they clearly put out a better line-up than you. Here'd be my personal ratings for each team based on current playing ability on that day (warning I'm not an expert on either team so they might not be perfect. Also my match-ups might be a bit off too). Ratings out of 10 for each player in brackets.
Roughead (6) > Stanley (4)
Morris (5) > Siposs (4)
Murphy (8) = Fisher (8)
Young (5) < Gwilt (7)
Johannisen (5) < Dempster (7)
Goodes (5) < Roberton (6)
Picken (5) = Geary (5)
Griffen (10) > Dal Santo (8)
Liberatore (7) = Hayes (7)
Boyd (6) < Steven (7)
Stevens (5) < Montagna (7)
Smith (4) = Ross (4)
Hrovat (3) = Newnes (3)
Macrae (5) = Ray (5)
Lower (4) = Jones (4)
Minson (9) > McEvoy (8)
Jones (5) < Reiwoldt (10)
Williams (5) > Hickey (4)
Addison (4) > Webster (3)
Dahlhaus (6) < Milne (7)
Giansiracusa (6) = Saad (6)
Stringer (6) = Maister (6)
Now I think if anything I've been generous to the dogs. Yet still I have you 6 points behind in total. In any case I think it's hard to argue that you put out a stronger team player for player than the Saints that day. Yet you got the win. Same with the week after against Port. Of course if you looked at these 2 teams and where you'd expect them to be in 3 years time, the dogs would be miles ahead but potential doesn't win games for you right now.
It's easy at 3-9 to say you've had a terrible year but week after week McCartney's got less current ability at his disposal than his opposition coach. The fact he's got 3 wins out of them is pretty impressive considering what he's had to work with (I'm not denying there's also been huge disappointments). Of course the test isn't whether he can get wins out of an ordinary list but whether he can make the young players reach their potential so in a few years time he's got more ability at his disposal than the opposing coach because in the vast majority of cases the team with the better players wins. It's far too early to judge but there's signs that he's developing a very talented group.