So we all know that Tobias Harris started this series playing like hot garbage.
To be fair, we knew going in that Kevin Love was an incredibly difficult defensive assignment for Harris, and in fact that is a problem we never really completely solved--if Harris was left alone on Love, Love could abuse him inside, but when the team provided help, the Cavs would pass around for an open look, and right to the end that remained a fatal weakness in the Pistons' defenses.
But the hope was that Harris could at least try to help expose Love's own defensive limitations, and for the first two games of the series, that was a complete failure. Some numbers to tell the tale: in the first two games, Harris shot 7-22 overall (0.318), 1-5 from 3 (0.200). He did average 9 rebounds (much needed) and 3 assists per game, but he also averaged 2 turnovers per game.
So in a series where one of the main storylines was that the young, inexperienced, No. 8 seed Pistons showed no fear going up against the Cavs, Harris was a glaring exception.
However, in the last two games of the series, Harris was a completely different player on offense. He finally started attacking the Cavs' defense, and Love in particular, the way they had need all along. And with the Cavs resolutely trapping Reggie Jackson, the Pistons increasingly leaned on Harris to generate halfcourt offense. Again, the numbers tell the tale: in the last two games, Harris shot 14-24 overall (0.583), 3-7 from 3 (0.429). He also kept up the rebounding (10 per game) and assists (3 per game), and cut his turnovers to 1 per game.
Or, if you are a fan of advanced stats, consider his TS% and ORtg by game:
Game 1: 0.409 and 75
Game 2: 0.448 and 109
Game 3: 0.650 and 121
Game 4: 0.710 and 140 (!)
Indeed, if you want to understand why Game 4 was the closest of the series, despite LeBron and Irving continuing to make big plays and JR Smith shooting out of his mind, look no further than the fact that Harris finally decisively outplayed Love. Of course Harris still needed help defending Love inside, which is what led to some of those big shots by other Cavs. But this was the first successful execution of the only gameplan for dealing with Love that could possibly work with the Pistons' current roster, and that was thanks to Harris massively improving his play on offense.
The big picture: Harris was such a steadying influence on the Pistons' offense during the regular season that I think it was easy to lose sight of the facts that he was himself still very young, totally lacking in playoff experience, and of course he had the least experience playing with the Pistons. That certainly showed in the first two games, but Tobias then recovered and came on very strong.
So in my view, he ended the series as the offensive asset we will need him to be for future playoff runs, and therefore ultimately emerged as one of the bright spots in this series, despite his horrific start.