^ Ok fine. I'm a web designer, front-end and sometimes back-end developer with 15 years worth of experience. I think that gives me an insight into coding things.
To my mind what Apple have done with both the calendar and music apps is well... it's crap. They've taken out features that worked perfectly well, features that at a guess a lot of people used. Picking an album from an artist with 20 or so albums used to be a simple process, now there's excessive scrolling or typing a search. Yeah, I'd want to type when I'm walking along a street and just want to play an album. Someone obviously decided it would be "kewl" to mirror the functionality of iTunes but forgot that typing on a keyboard when stationary is a different thing to trying to type whilst walking. They have borked the interface and I'd say that's an issue, whoever decided to do that frankly needs a slap.
Also, I would never take legal advice from an online forum.
I can agree that people see lots of differences in those apps and would like to know my self why they changed (could it be because of back end DB coding and efficiency concerns that these were made, or is it not possible to have them work the same way with the new back end in use, or was it just coding left out/ changed that could be added back in the future, i think this is more the case for these issues? I experience this day to day with the product I support and when the dev's changed the backend framework in the new version, older functionality had to be lost as the new api's and coding didn't support that functionality. It was an impossibility with the new framework. Customers were unhappy, but there is nothing that can be done as the framework just couldn't and didn't support it, This made it a problem and hardship for some customers, but it didn't make it a bug. It works as it had to be designed.). I don't necessarily see this functionality as an issue for me, but there is definitely a change in the functionality. I just think that changes in apps should be held on their own merit and not attributed to the OS being crap. Too many on here complain that the OS is the issue, when in reality it is the apps they are complaining mainly about. I would rather have it this way as apps can be had within the App store easily enough to gain functionality desired (the stock calendar could easily be replaced today or a week ago to get the view required), but issues within the OS will be there until the releases are updated on an as need basis, which could take some time.
I agree that there are differences with the OS, but I just don't think the OS is the reason for all the complaints, as it seems stable on all 5 of our iDevices.