Future steps... So I've been thinking of the issues most people have with Arcadeflow...
Someone mentioned cropping of videos in box art mode, I'll see if I can think of something, but at the moment I think the worst issue is the cropping of (artwork box arts or snaps) in the main UI. Currently all displays are adapted to 4:3, 1:1 or 3:4, but this means a bit of cropping for Lynx or Game Boy Advance for example.
As mentioned, it would be great to add proper AR independence, but that might need huge rewrites or compromises. At the moment I plan to just add _more_ ARs, so that many displays won't be cut at all, and less cutting will be needed.
I've come down to select 7 AR: 1:1, plus 3 horizontal and 3 vertical. The horizontal ones are 4:3, 3:2 (GBA) and 10:9 (Game Boy). I've done some evaluations of ARs of many system and it seems this would be a good fit for many box arts too... The chart shows dots for the real AR, crosses where the new AR are. Pretty close to many solutions, to the point that maybe I could even use "non cropped" box arts...