I'd wager 90% of those 2014 trips were for the infotainment system, which has been significantly updated software wise for 2015. Mazda has also been reliably releasing updates for the 2014 Mazda 3 software (which I believe is the software now in the 2015 6). It's still not perfect, but it's much better than it was at release, and continues to improve. Like many new vehicles with infotainment systems, it's a work in progress.
The nice thing (assuming you don't mind the risk) is that the Mazda infotainment is a Linux kernal very similar to Android, and already people are working on modding it and have successfully done some things for the Mazda3.
As a proud owner of a 2015 Mazda6 Touring....
I absolutely LOVE!!! the car. One of the few cars you can still get with a manual. I drive the snot out of mine and still get @30mpg with mostly city driving. Steering and suspension feel is superb for a family sedan, and the car looks gorgeous from any angle. I drove the Fusion and the Accord and it was no contest picking the 6. I just love how Mazdas feel/drive, and the 6 has that DNA in spades.
The only "issues" (TSB) I have seen in the 2014-15 is for spiders in the evap system (no I am not joking), and "wind noise". Both corrected for 2015. I personally have no issue with wind noise. There are also a few complaints about rattles in the headline in sub freezing temps. This is fixed by tweaking the clips that hold the headliner up in the rear.
The Mazda6 does
NOT share the infotainment system with the 3. It is closer to the CX-5, and it is the weakest part of the car. I love the "Commander Switch" on the center console, and it is the ONLY reason I haven't replaced the head unit. (It is a big plus that you can replace the head unit with any double-din radio. Unlike the 3 that has the large display sticking up out of the dash.)
"Issues" with the Mazda6 infotainment system:
1. Downloads address book every time you turn the car on. - This simply blows. It takes a good minute or two to finish pairing.
2. Tom Tom Nav - The OEM unit uses Tom Tom, and by all accounts it is a terrible implementation. I could add it to my Touring model for @$400 by plugging in a module, but the consensus on the Mazda6 forums is to use your phone or an aftermarket dash unit. My phone works fine, and even plays voice prompts through the speakers.
3. Pandora integration - Works flawlessly 80% of the time. Other times I have to reboot my phone or force stop the Pandora app to get it to work with the car controls.
4. Message downloading never works - The system is supposed to download and display text messages that come in while you are driving. if you have more than @15 messages (for all conversations), it will timeout and fail to download and display. It is a completely worthless feature.
"Likes" with the Mazda6 infotainment system:
1. Commander Switch - My car is a manual and my hand is always near the center console. It is very intuitive to change the phone and audio settings once you learn how to use the switch. The only reason I haven't chucked the OEM head unit.
2. Phone and Bluetooth audio works great. - I listen to podcasts and audio books all the time, and the system never has an issue pairing and playing back media.
3. HD radio - Works fine, but I rarely listen to commercial radio
4. Build-in backup camera - Yeah it is a "nanny feature", but it is a nice supplement to turning your head.