I'm not sure we would have seen a Roy/Pierce/Big Al combo for long. Pretty clear that Pierce was getting very frustrated with all of the rebuilding, had we not made the deals for Ray Allen and KG I'd be shocked if he wouldn't have asked for a trade. He might not have gotten traded, but the dynamic would be wholly different. He'd clearly had just about enough with playing with the young kids.
That may have come to pass but PP may have been willing to see it out as well. Assuming the players we had would have stayed with us (no trades for Ray or KG nor speculation on other deals -- just to make my life simpler here) and Danny made the other moves that weren't related to the Ray/KG deals, the team would have looked something like this:
Starting Line-up
Rondo (Danny still purchases the pick),
Roy, PP, Al, Perk.
-->that starting line-up still has 3 prime-time scorers with Rondo and Perk.
Bench
Delonte (hopefully with his act together),
TA (hopefully pre-injury-->if the trade with Portland doesn't happen, the moment in the game where he injures himself possibly doesn't come to pass --> go with me on this one on a whole time continuum sort of thing),
Gomes, Powe (Danny still acquires this pick),
Green/YI-->Danny keeps this pick and either takes the player that was picked or the one he mentioned he wanted--hopefully he takes Green,
Giddens, Hudson, Walker (Danny still gets the Walker pick from Washington. Danny would have also had last year's first rounder to add. I would also speculate that Telfair, Gerald and Pruitt would not be with the team.
*one speculation that's feasible, if Danny doesn't have 2 2nd round picks when Pruitt and BBD are available and based on the roster mentioned above, Danny may take BBD with C's pick instead of Pruitt. Not exactly a stretch and would strengthen the "alternative universe" roster.
Add a free agent big man for each of the last two years with the MLE to back up Al and Perk and that's a team that can get to the ECF if not the finals. Definitely a lot of depth and a quality starting line-up.
Pure speculation obviously but not necessarily a gloom-and-doom situation.