The problem right now is Mike Brown hasn't figured out his rotation with Wallace out and with Joe Smith. Anderson was the guy who came off the bench and guarded centers well. Joe Smith can't really do that as well as Andy could. The Cavs always seem to figure their defense out by the playoffs.
And, you are painting this with a broad brush.
The first Lakers game they got killed because of not having Z. Ben Wallace was on Bynum, and he couldn't stop him because he was about a foot shorter.
The second game against the Lakers they played poor weakisde defense and couldn't stop dribble penetration. It was not even close to the same as the first Lakers game. It was guys getting into the paint and passing it across the floor on the weakside. It was Pau getting doubled and passing to cutters. Deltone was out remember and that is who usually guards a guard like Fisher. The Cavs also had fundamental issues like boxing out
The Celtics killed us last week in a true battle of the paint
Last night was a ton of fast break and slop plays by the suns. It's not as if they were passing it down into their bigs and scoring all from there. Again, different- and as we have seen, that doesn't happen in the playoffs