Re: I don't think that was ever the case
Just to add to Larry's good description, the heat load from a straight-in descent would exceed the thermal protection systems' capacity. This would be due to the extra time it would spend in the upper atmosphere after an earlier-than-normal deorbit burn. Ron Dittemore has repeatedly said that there is no way to mitigate the thermal load experienced during entry. You can make it worse, but you can't make it better than it already is.
-Kim-