I think the Big Three have 1-2 years in them after this season. Honestly outside of trading one of their big three there isn't much the Heat can do to add to their roster. Same with Chicago unless they trade a major player as well. Both teams are stuck with the Mini MLE as their source for adding to their roster.
Orlando will likely trade Howard and rebuild, but they were never a threat anyway to Boston. Indiana is still young and so is Philly. Also, especially Indiana, they likely use their cap space to extend their young players. NY is stuck with Amare's deal. If Brooklyn can get Howard then they even would be a year or two away. Obviously Atlanta will likely make changes, but it's unlikely they improve.
My point is that Boston is really in the best position to improve their team for the next season or two without hurting their future. And if you can make it to the Finals then as Dallas showed, and as KG knows, ANYTHING IS POSSIBLE.
It looks like the cap will be around 60-61 mill. That means if Bass doesn't opt-out we have around 25 mill in cap space. Not counting draft picks. Give KG a two year 20 million deal and Ray a two year 11 million dollar deal (5 in yr 1 and 6 in yr 2). Make the second years both player options also if that gets deals done. That leaves roughly ten million to sign our draft choices, and maybe bring back Pietrus. Also give Steimsma and Bass a little raise if Bass does opt-out. Use the 2.5 mill exception after we reach the cap for Green on a prove it deal.
We might then have enough money to bring a guy in on a cheap deal or even via trade also.
So our roster could be: Starters - Rondo, Avery, Pierce, Bass/Other Player, KG
Our bench could be: Ray, Green, Bass/Other Player, Pietrus, Stiemsma, Jujaun, Etwaun, 1st pick, 1st pick, and 2nd pick.
Not sure what "Other Player" could be from a salary standpoint based on our cap room and what we could trade in terms of a 1st or something. Maybe a Paul Milsap? However we could be vastly improved next year where as all the other contenders in the east will likely be unable to improve too much unless there is a major shakeup of some sort.
I say line up as many contracts as possible with Pierce's deal and then Rondo's deal after that and see what happens with the cap space in a couple years when a guy like Kevin Love can become available.