All in all, I see two reasons why I do not like this:
- home button issue as mentioned above (ok, it may not be as bad as it used to be, but still potentially makes a device that was useable with the old OS unusable with the new one);
- precision: as I am using my iPad as an alarm, and typically do not want to be searching for the home button to unlock it; since the alarm activates the lock screen, I now have to...
Probably this is no biggie, but, to me, it shows that smartphones/tablets are still far from mature from a UI point of view, and since the main paradigm seems to be not to leave users much choice about how they will deal with the interface (I cannot count how many applications have at least one gesture or "feature" that aggravates me to no end, and cannot be deactivated). And as usual, this version of iOS fixes some of these things and breaks others.