Hi. First of all, thank you to the developers for the great work you put in the site. One of my favorite ways to use lichess is to prep my tournament repertoire. The master's database serves as a great help for that. One feature that would be a great help, in my opinion, would be an option to filter out all of the blitz games. For (most) blitz tournaments, the first line of the pgn contains the word "Blitz", so while a filter might not be perfect, it would still eliminate most of the blitz games.
I think this would help with preparation because many of these blitz games are decided by a sudden blunder, so the statistics in a line are not necessarily representative of what could be expected in a long time control. One issue that I could see, however, is that it might be computationally expensive to apply a filter to a data set as large as the master's database. That being said, I wanted to put this idea out there, since, if feasible, it would be a great assist for selecting opening lines.
I think this would help with preparation because many of these blitz games are decided by a sudden blunder, so the statistics in a line are not necessarily representative of what could be expected in a long time control. One issue that I could see, however, is that it might be computationally expensive to apply a filter to a data set as large as the master's database. That being said, I wanted to put this idea out there, since, if feasible, it would be a great assist for selecting opening lines.