Simplified did away with it entirely. I can see some situations where the ending -rt would be slower than the reverse vowels. Sometimes when you write the r sound you feel like you're putting on the brakes to get the t connected to the r. But I guess getting rid of the reverse vowel system got the go- ahead from Gregg himself, since he was still alive when Simplified was being created in the 1940s.
One other thing, I never did like the j-nt blend in Simplified (also in older systems). This is one situation where I think DJ did a service because it omitted this blend. It always seemed confusing to me to have the same blend for p-nt and j-nt, etc.