I got McClain's consistency up last.
I first got his PRC, AWR, BSH, TAK, POW up to 90. Once he got there he was pretty much "consistent". Honestly, now that he's a 4 in consistency...I can't tell a difference. He made 150 tackles/year before and after...I really can't tell the difference in his production.
I haven't done it on a QB yet, still raising his main attributes first. Same for the WR, though I gave some to Moore, and, again, can't really tell a difference. How bad is a guy with high 80's in his main attributes along with 95 SPC, 94 SPD, and the ACC/AGI to run routes going to be, though?
DBs - sometimes they go soft on me, but is that because of consistency or because they still have weaknesses in their main ratings? One corner has 60s AWR, another is low 80's in PRC and AWR. My third corner is okay, but not great in coverage and has average AWR.
OL - same thing, got strong young talent at LG and RG, mid-90s STR and the RG has high 90's RBK. His consistency is now 2, but he still seems to play the same way.
For a HB - Caulder just owns for me, even without high consistency, especially once I got his BCV close to 90, CAR in mid 80s, and AWR up close to 90. His 90s TRK does the rest.
I think it might matter more for average guys - but, then again, so would making them not be average. The point about DEV rating makes sense, but, then again, McClain is Normal DEV and he was good before I upped consistency once he turned into mini-Willis.
May depend on how much I plan to use them. For a back up, or that guy that has a one-off awesome game, consistency might be the way to go. They won't go cold from sitting around or doing very little in games while increasing attributes matters less since they'll play less.
For everyday guys, I can't see raising CON over their regular ratings. 80% of a higher number is still getting better production - so his 'down days' and 'plays off' are still productive, they just won't be awe striking. Just the way I look at it, though.
Big Hitter: That's a good trait if the player has the TAK and POW to back it up (i.e. not fail on the big hit). There's a big difference between McClain's big hits and Tyvon Branch's.
High Motor: I loved this one from M12. Too bad it's not available for all positions (wonder why?), though any position can have a Yes there. Next best thing on defense is high PRC and PUR.