While there was clearly an awful lot wrong with that Juve performance, it was a good exercise for them in terms of gaining experience in two-legged knock-out football. Very awkward to get the balance right as an away team when you are playing a decent side who are determined to play as negatively as Lyon did.
I thought Juve got their approach about right. 0-0 wouldn't have been a bad result, so there was no reason to go committing too many men high up the pitch and risk getting caught on the break. That was particularly true in the first half when there really was no space and so Juve were't likely to gain from taking risks. In the second half the game opened up a little around the time Vucinic came on and Juve did pretty well in exploiting the spaces that appeared and really should have scrored before they did.
That said, if you go into the details of the Juve performance, it was very poor - particularly in the first half.
The movement from the midfield five and the front two was virtually non-existent. If you are being man-marked, you need to try and rotate the positions of players to ask questions of the markers to see if they are prepared to leave their zone to keep marking and to see if players switching positions can create some confusion. Even if markers couldn't be lost, you should be able to manipulate the opposition to enable you to create a one-on-one situation somewhere in a bit of space. That should have been easy to do wide (though Juve's wingbacks aren't terribly likely to beat a man one-on-one) and should have been possible to create in a more central area with Pogba or Tevez if Juve had shown a little more guile.
However, you could argue that the movement required to open things up would have left Juve more exposed and that may not have been a risk they were willing to take in the circumstances and I wouldn't particularly criticise them for that, though I would still suggest they could have done a lot more without risking much.
Felt sorry for Bonucci in the first half. He ended up looking bad with how few of his passes were coming off, but the players in front of him were moving so poorly that he barely had a target to hit.
Anyway, it's a good result for Juve and should be enough to see them through.
On a side note, (almost) regardless of allegiance, I do love to see a team who have played an incredibly negative game lose to a late goal.