I wonder if it has anything to do with the durometer of the rubber (hardness/softness). If they are using a softer rubber then perhaps the finger ridges were too weak. I've never found that the finger indents do that much for me.

The new one seems to undercut the trigger guard a bit more putting your hand higher relative to the bore axis.

The cost of these grips is directly related to the weight of the rubber. So unless the new grips weigh a lot less, then I would think that they made the change for other reasons.

Someone could query S & W directly at their site and find out their take on this.

As for ugly. I had a 629 with a round butt and 2-1/2" barrel back in the 1980s. The beautiful wood grips caused a bone bruise on the ball of my thumb that took 6 months to heal. The "ugly" rubber grips did not. So sometimes "ugly" is beautiful.