No doubt Maroney is a bust. With a potent passing offense and TB, Moss, Welker being the very best of their positions (QB, Wideout, slot), the running game can be successful with even average talent. You could argue the team has been more successful with Morris, Jordan and BJEG. Maroney has performed like a 5th rounder so far; he is not worthy the 1st round pick the team wasted on him.
Look Joseph Addai, who was picked after Maroney in the same class. The guy is lethal in Colts offense. No doubt he benefited also from a potent passing offense with Manning and Wayne. But Addai has consistently gained 6-7 yards a pop; he carries colts offense especially in playoff. The guy is also a first-down machine, converting like 75-80% of third down carries into first downs. He is an excellent receiving threat coming out of backfield. Remember he turn a dump-off pass into 72 yard touchdown catch and run just before half-time in the last game against Pats?
Addai is a much better runner, better blocker, much much better receiver than Maroney. Addai was drafted after Maroney, costs less, and played much bigger role to Colts offense than Maroney has ever been able to achieve.
Maroney was drafted in the first round, but can easily been replaced by guys like Jordan, BJGE. His contribution to Pats is limited. Therefore he is a bust. No doubt in my mind.
There were ramblings about Maroney and Chad Jackson's work ethics and maturity a couple years ago. Maybe the source of lack of progress
.