Last year, the Celtics and Bulls both owned the Heat in the regular season. We all know how that ended in the postseason--- outright dominance by Miami. If they meet, I think the Heat are stronger this year and the Celtics will be weaker. Here's why:
If they meet, the Celtics will be tested by the Sixers in the 2nd round. They will have to utilize quite a bit of energy to overcome a pesky squad which knows them well and handled them easily twice this season. The C's bench is not deep at all and the Sixers bring a thunderous 2nd unit to the floor. This will deplete their reserve of energy coming into a (possible) Miami series. I don't discount the fatigue factor, especially when it comes to KG, Allen and Pierce. Last year, the Celtics had the benefit of sweeping the Knicks and meeting Miami in the 2nd round---they were well rested and they still got beat 4-1; this year, they will enjoy no such rest and will likely have played 6-7 more playoff games prior to seeing Miami.
The core of both teams are still unchanged and Miami has already proven they can win against Pierce, Allen, Rondo and Garnett in the postseason. There are no demons going on this year with LBJ and the Celtics. Those were banished last year. He singlehandedly destroyed them at the end of game 5 last year. He and Wade averaged almost 60 ppg in those 5 games.
Wade, Bosh and LBJ athletically outperformed the C's last year and I don't see why they won't once again. Rondo is amazing, but can Pierce, KG and Jesus bring it and sustain it for a possible 7 games? I just don't see it happening. They are all one year older and not with a better supporting cast.
I don't envision the Celtics supporting cast outperforming Miami's. The Celtics actually had a better cast last year with Delonte West, Von Wafer and Glen Davis. The Celtics, this season, only go 7 maybe 8 deep, realistically, and this will hurt them significantly against the Heat(who can go 9 deep easily). Though I like Bass, he is not an upgrade over Big Baby(as evidenced by Davis' performance with Orlando these playoffs). Pietrus can shoot, but is one dimensional and not the ballhandler that West was. Bradley is solid. Their frontcourt is where they will be exposed. Pierce and Garnett cannot be expected to expend too much energy on rebounding. The C's are small upfront and their rebounding is horrific. Stiemsa truly sucks. Anthony, Haslem, Battier, LBJ and Miller should be able to outrebound the C's frontcourt.
Finally, LBJ and Wade are on a mission to get back to the Finals and win it all. I think their motivation is greater than Boston's to reach the championship. They are hungry in a way the Celtics are not.