The MPS3 was never mean't to be a rival of the WRX. It was positioned for the Focus RS/ Golf GTi market. Same goes for the 6 MPS. ie: Liberty etc. The MPS 6 platform was good, but far to heavy. And expensive.
I like the new shape. It updates it in line with the rest of the models. It was looking dated. Disapointed it's not a complete new platform, but the old one was by no means bad. It did suffer from NVH issues, particularly in the hatch, therefore it'll be interesting to see if that's better. It should be.
I had a number of opportunities to drive the old 3 back to back with most of it's competitors, and it was a good thing to drive. If you got over the interior looking like the interior of Darth Vaders helmet. A little black light would light up in black telling you something in black that you couldn't read.....However, I considered it to be one of the best available in that market. Cosidered one for Mrs Dwarf very strongly, before spending a little more for a Golf (and getting a lot more car.)
The update can only be a good thing for Mazda. The old one sold hand pver fist, and I expect the new one to do the same.
As for the looks of the new MPS, the bonnet scoop looks like it will suck in children and small trees. Too try hard for me.