Sure, Ray has shown that he is becoming more and more streaky as he ages (it's almost all or nothing with him now) but people who think that him leaving wouldn't kill us are either blind or really optimistic. Sure, theorically you can replace a shooter by a shooter, but would you really feel good if Ray was replaced by, say, J.J Redick?
Not to mention all the difficulties to get a really good shooter considering our tight financial situation.
Considering how bad our offense has looked all year long (and especially in some games/stretches during the playoffs), envisioning it without Ray to create some space is just an horrific vision... if he leaves, we're in big, big trouble so I hope he doesn't.
Regardless of the fact that he is my favorite player, Ray is a key piece in this team that often gets overlooked. He creates spacing. A lot of spacing, actually, and nobody else on this team creates spacing like he does. Imagine a starting 5 of Rondo/TA/Pierce/KG/Perk (when healthy). The lack of shooting/spacing would absolutely kill us. And a guy like Redick would improve this situation but clearly wouldn't bring what Ray brought.
To me, Ray is as crucial as Rondo for this team, so if he leaves... ouch.