A few things:
1) The way Doc leans on Ray at times clearly shows the respect he has for him. There's been a number of key games this year when Ray's played over 40 minutes when no one else has topped 35. That clearly shows you how much Doc values not only the spacing his shooting supplies, but also his ability to handle the ball (which helps with House in the game).
2) You really can't emphasize what his spacing does enough. People like to complain about all the threes Ray, Paul, and Rasheed take, and all the 20 footers KG takes, but if this was a team of slashers (like Rondo) this many scorers on one team wouldn't work. Not only is Ray so valuable for how he can open up the floor for others, he's also valuable because he can go off for 20+ points without having a play called for him by just hanging out on the perimeter waiting for a kickout. (Of course, he can also get his own shot.) And that goes a long way for getting everyone their touches.
3) I wouldn't worry about his shooting. Despite his age, he might be in the best physical shape of anyone on the team. Furthermore, even when his body starts to fail him, it won't be his shooting that goes, it'll be his quickness, etc. Expect him to be in the upper 30% by the end of the season at worst.
And as people have already said, even if that doesn't happen, the fact that he's Ray Allen will keep teams from cheating off im for a very, very long time. He'll have to have several 32% seasons before teams start to leave him alone.
4) Baby. Aside from the fact that playing him at the 3 is probably a bad idea (especially for long periods of time, as he would as a starter), the value of Ray coming off the bench would be dramatically diminished come playoff time. I mean think about it, do you see Doc playing the starters less than 36-38 mpg come playoff time? Isn't it likely they're playing closer to 40? What that means is that there's pretty much always going to be 2-3 starters on the floor at all times. It also means we'll probably only use 3 bench players. So having Ray come off the bench for "instant offense" isn't going to matter if Pierce, Rondo, and KG are still on the floor. Finally, I'm not convinced that Baby can even crack our playoff rotation. Yes, he probably will beat out Williams by the end of the year; however, if KG and Perk are both playing north of 36 mpg come playoff time, do we have minutes for more than Wallace? I'm not so sure.
