Indeed, I'll never understand hopw anyone could be against this rule, it is one of the best changes they ever made.
The rule as it stands right now has drastically reduced the number of pucks being put into the stands. And that's a good thing. Trying to remove it - or weaken it - is like removing *insert random car safty feature here* because fewer people are dying in car crashes now then they used to. There are less deaths in car crashes because they exist, and removing them won't somehow keep safety at that level. You change the rule about putting the puck over the glass, and you will see a considerable increase in just that happening.
And more to the point: why oh why does anyone want players to be able to take the lazy way out / cheat?
If a player is under pressure, he needs to make a play. Any reasonable hockey-fan should aim to make sure that he has to try and make a proper play, not chuck the puck wherever he wants to get out of pressure. None of the proposed alterntives to the current rule are in any way enough of a deterrent. Players would gladly face any of them compared to the risk of losing the puck in their own zone.