There is a big difference. Also notice the flat area in the middle of the old ones it is huge. A lot of surface area for water to build up under. Then the side channnels on the new pattern connect the inner and outer groves also allowing for more water in the middle to find its way to outside of the tire. The side channels are also staggered allowing for even more water to be dispersed easier. So there is 3 improvements on the new design.
I have driven these tires at highway speeds in the rain several times and didn't spin out and wreck my car.
I have had this car since it's been new and it has a 146k on it. I have driven it in countless rain storms and I can honestly say that they are no worse than some of the regular street tires I have used. Hell I just went to Baltimore from Wv a 4 hour trip each way. It rained almost all the way back.
I do not think they are a great rain tire. But if there is decent amount of thread left on them and you don't drive it hard you can make it home safely if caught in the rain. There's been many people hydroplane and wreck these cars with regular street tires on them.