...it was always personal with Sonny.
And it shouldn't have been.
...Sonny was emotional, and he was impulsive BECAUSE he had a big heart. Maybe Vito and Michael would have done it different, but that's what made Sonny special...
Sure, he had a big heart, and he was 'special'. Doesn't mean he didn't repeatedly display psychotic behavior, even if he arguably wasn't an outright psychopath.
He did things differently than Vito & Michael would have...and that's why under his watch business suffered and he ended up dead.