BVB deserved to go through, but they did not dominate Lille at all
I don't particularly believe justice exists in football, as it is likely the most unpredictable sport in the world. Therefore, a sense of justice, or the concept of who is the most deserving to win, becomes entirely relative.
Overall, I think if there was a side to be considered the deserved one to reach the Champions League quarterfinals, that side was Borussia Dortmund. However, that was a more balanced matchup than most people would have thought. Considering Dortmund's season so far, I believed Lille would pose a difficult challenge to the Black-and-Yellows, which probably would have been crazy to say in other scenarios.
Kovač's side was indeed the most effective and deserving due to their chance-creation as a whole, but they did not dominate Lille at any given second in those two games. The French side showcased a lot of defensive solidity and organization as a unit, which ultimately made BVB struggle as they watched their chance at the quarterfinals disappear for an entire half. Therefore, as much as it is the right thing to give props to Lille, Borussia Dortmund will need to show more if they want a shot at beating the Spanish powerhouse in Barcelona.