Nope. It rains in April too and is frequently soft then as well.
He shot the lowest score of anybody in the field 3 out of 4 rounds, including the last day, increasing his 4 shot lead to a five shot win.
Sure the course was soft, but there were other barriers to scoring including several rounds that took more than one day to complete, frequent mudballs(he often laid up on perilous par 5's due to this), scruffy conditions and was quite windy the last day, where he tied the low score of 68.
There are ALWAYS scores lower than 68 on their normal roar inducing final round setups.Today there wasn't, indicating a tough final round course.
He shot the lowest score in Masters history, and I would argue he would've won by more without the parity inducing softness-I seriously doubt Smith would've been anywhere near the lead with firmer faster conditions after that scramble show from frequently way out of position.
Perhaps, if several had beaten or tied the old record I would agree about the asterisk. For now, good on DJ on an impressive win.
I will concede Tiger's was impressive due to margin, but that was a 500 yard shorter course, and no asterisk was beside that.