#3 He didn't get that far as a heel
The fact that Samoa Joe never reached the World Championship level as a heel is slightly disappointing. He proved to be among the best promos in the company and had no issues when going in the ring.
Joe is a world champion caliber talent and should have reached that level but didn't because WWE clearly only saw him as someone who made others look good. One of the negatives you usually hear about management from creative is that they view their own booking failure and attribute it to the superstar, which is probably why they feel he'll have a bit more success as a babyface.
Either way, it's most definitely worth a shot and we hope for his sake that the babyface turn does work out for the better. He deserves a big push.