My understanding of the RICO drilling is it tries to get the ball to react earlier than normal. If you adhere to the Dual Angle method, the RICO tries to get the after drilling MB further away from the thumb by putting the big balance hole at some distance away from the normal post drilling MB (thumb) on a symmetrical ball.
By lowering the drilling angle, and to keep the totals in a preferred ball park, the VAL is increased and having the pin in the palm of the grip. Without a thumbhole, I guess you could have the MB closer to the balance hole, but I wonder how large the post drilled asymmetry would be since now you have one hole instead of two.
The problem most people have with the RICO is the drill is set while the variable is the bowler. This means a RICO drill will behave differently for each bowler since each bowler's PAP is different.
I personally have had a RICO drilled ball, but it wasn't anything special. I now keep to a smaller range of drilling angles and use coverstocks to control more of what I need a ball to do.