I find this a little irksome too. Not only the bright yellow overlay when your style skill is active, but the blue overlay on slowmo activation too. On bright maps the yellow overlay is too bright and on dark maps the blue makes everything dark. Thing is though, it's great feedback for the players to have. The slowmo more than anything. If you aren't the player that popped slowmo then you need as much feedback as possible that someone else has. Otherwise new players would be confused as to why they are getting owned slowly.
I see two solutions. Either normalize the lighting across maps so the overlays aren't so intrusive, or change the overlays.
If we normalize the lighting across maps (ie bring the ambient up on streets and down on rooftops - which D has already done) we risk making the maps lighting bland and monotonous. Personally I like dark areas with harsh lighting - it adds a lot of detail and interest with little overhead. Being able to capitalize more on that in the maps would be nice. The same way that external maps in a daytime setting should be able to have a bright sun.
As for changing the overlays, we have talked about it before. The style skill activation overlay could be toned down so it's not so yellow, but I think a local contrast boost (like in left 4 dead when you take pills) and maybe some slight radial blurring in the vignettes of the screen could provide enough feedback without becoming intrusive. Also I would like to make an animated electrical spark effect kinda like the one in guitar hero
to go on the style skill bar when it's activated.
The slowmo makes everything dark but again it's valuable feedback for the player. Maybe the overlay could be a brighter blue that won't bring the brightness of the whole screen down? We were also talking about having some kind of outline or radial zoom blur around the player who activated the slowmo, so you know where's it's coming from. That would kind of make players a target if they pop their slowmo though so I'm not sure if it would impact the gameplay negatively.
Anyone got a third option?