Another idea I came up with is to crack down on players pinning other players along the boards. I hate it when a player goes in to retrieve the puck and then a defender comes in and pushes a guy to boards and doesn't let off for like 5 seconds.
Get rid of the red line entirely. If dumping the puck in is mostly going to be for line changes anyway then nobody wants to watch teams defend the red line. Also widen the blue lines and soften the language of offside.
The NHL says it wants to speed it's game up and their solution is video reviews, taking time outs away from the coaches, and more delay of game penalties. This league never ceases to amaze me with the way they are out of touch.
More to the point, though, is that eliminating the red-line would create a two-zone game, akin to basketball. Like now, there would be a ceaseless procession of zone-entries by stretch-passes, with defencemen never leaving their zone, and the puck simply zipping back and forth between the two zones. But it would be even worse with no red-line because players would just endlessly attempt low-percentage stretch-passes, which, if they fail to connect (maybe 50% of the time), would alternately serve as a no-consequence shoot-in for a line change.