I also had the same issue in the summer time, and the A/C in the Mazda.
The air flow was not good... Now after the dealer replaced the Mode switch
the air flow is great...

Ok, This is what happened to me about the A/C and Air Flow.
It seems that the MODE knob was not working properly.

Here is an easy test..
Put it on A/C Max, Fan speed 4 (Max), and Mode knob on Vent (far left)..
If you move the Mode knob to the next spot (between vent and Vent/feet),
and you do not notice an air flow change in the middle vents, then your mode knob is broken.

Another way to test this is as follows:
A/C Max, Fan Speed 4 (max), Mode on Vent (a/c max)
Then move the MODE Knob to the right slowly.
If it gets hard to turn around the 12 O'Clock position, then you have a bad Mode switch. Check it going the other way too.. (From far right - far left).
Remember you need to turn the knob slowly.

It does the job, eventually.
 

Living in South Florida, I tend to use the A/C a lot.
I have a 30 min commute on surface streets with numerous stops for lights. On the way home, internal temp in the car when I get in is regularly three-figures.
I would describe the A/C as adequate. It takes a few minutes to cool the car, but once it does, it keeps the inside comfortable.
One other aspect no-one else seems to have touched on, is that at higher fan speeds it's noisy.