Scufo has a point. Theoretically, you could replace all sakurai angle moves with an actual default angle and not have the moves lose their purpose, but still work better.
Since the sakurai angle raises to a maximum of roughly 40 degrees, something along the lines of 35 to 30 degrees may be a place to start.
EDIT: Though after playing with the angle for a while, I think I also understand what Magus is getting at.
Characters, by default, don't rise to the actual angle that a move sends at until they are at a high enough percentage, regardless of the angle. I think this is due to simple character weight and fallspeed and such.
As for the fact that the Sakurai angle can be DI'd nearly straight upwards, that just seems to be an effect of the 40 degree angle it gradually rises to. Lowering this angle reduces the effectiveness of the DI upwards.
Which means that the sakurai angle is simply a 40 degree angle that has a chance to trip people, from what I can tell.
This means that the 40 degree angle is a terrible angle altogether for kill moves, it seems. For combo moves, though, I'm not sure. lowering the angle to 35 seems to preserve combos as well as reduce the effects of DI.
Either way, I think Sakurai just trolled us all. Hard.