The best instinctive shooters I know emphasize maintaining push-pull with your bow arm and string arm until the shot is released. The problem with holding 3-5 seconds is that rather than maintaining push-pull the shot becomes static, or worse, begins to collapse, i.e. the arrow is released at something less than a full draw. This problem doesn't occur if you release as soon as you reach your anchor.
However, releasing as soon as you touch your anchor may create other problems:
1. You probably won't shoot as accurately because everything is in motion up to the time you shoot, so there is no time to "aim." Instinctive shooters still need time for their mental computers to zero in on the shot, which is what we call aiming.
2. You may never reach full draw, since a common tendency among snap shooters is target panic: you are so set on releasing when you touch your anchor that you release early.
So how do we reach a happy medium between these two problems? The best approach I've found is to slow the draw way down as I approach anchor, maybe taking a full second to draw 1/8 of an inch. This allows me to maintain my push-pull throughout the shot, but also gives enough time for things to stabilize which seems to give me more accurate shot placement. This isn't the only approach that works, but it works for me.