I think the problem with the edit is that it's inconsistent. First of all, the beam PIERCES through both Raditz and Goku (this is clear as it's seen by the audience), yet Goku's wound doesn't show any sign of being an open one. The purple stain makes it looks like it's a bruise, but definitely not something that shows something has gone through a person's chest.
Now, if they HAD to tone the scene down, they could've cleaned up the spilled blood (they were allowed to show blood on Raditz, so it's not entirely taboo), and keep the black hole in Goku's chest with SOME blood on it for the scene to be convincing.
Or, they could've edited the piercing scene so that Piccolo's beam goes through Raditz but not Goku (i.e. removing the beam coming out of Goku's back). Then the purple bruise would have actually made sense.
Of course, it makes little sense how someone who manages to survive plenty of battles with broken arms and legs dies from a PUNCH IN THE STOMACH. Oh well.
Also, the purple bruise looks terrible from a technical standpoint. Even if you've never seen the original, it's pretty easy to tell it was imposed later on.