It looks to me like the Cavs are, in fact, too small. Suggs is bigger than Mitchell, Harris is bigger than Garland, Franz Wagner is way bigger than Okoro and Strus and can shoot over them at will.
Banchero is not taller than Mobley but he's a lot stronger and last night he slammed into Mobley enough to create space to shoot his fallaway.
Guys coming off the bench like Mo Wagner are bigger than Niang. LeVert is too skinny to defend guys like Suggs.
Being either shorter or skinnier than the Magic at every position except center was not a problem as long as the Magic were shooting 32% and missing 75% of their wide open shots. But once they settled down and started making those shots the Cavs had no response.
In order to beat a taller, stronger, and more physical team it takes skill - better ball handling, passing, and shooting.
My concern is that neither Garland or Mitchell are 100%. Strus is a complementary player; he doesn't create shots on his own. Same for Allen, Mobley, Niang, Okoro, and Merrill. It all depends on Garland, Mitchell, and LeVert to beat their man off the dribble and either knock down the shot or pass to an open teammate after another defender picks them up.
If Garland and Mitchell are playing with a back injury and a sore knee and can't hit their shots (they went 8-for-26 last night) and LeVert can only make layups then the offense is in a lot of trouble. They still haven't scored 100 points.
Niang and Strus were brought in after the Knicks' debacle to provide 3-point shooting. They're 6-for-30!
The problem is not lack of effort or toughness. These guys can't shoot straight.