Cooking, Fishing, First Aid: The secondary professions no longer require the purchase of books to train. You can now go to the appropriate trainer and just pay to level up. Hot Spices and Soothing Spices are now obsolete. If you have some in your bags or bank, they have become grey and can be sold. Most of the recipes have been reduced to meat only, so apples are no longer needed for the Jungle and Strider Stews, for example. Overall, cooking, fishing and first aid got more convenient to level and there are better rewards.
Dual Specs: Dual Specs are implemented and everyone is doing it. Even if you don't raid, they are very convenient for those who both PvP and PvE or players who split their time between soloing and grouping. So, save up 1000 gold and if you are over level 40, try it out at your nearest class trainer. You'll also need two sets of glyphs to go along with your two specs, so make sure you have those covered as well. And check out your class column here at WoW Insider for advice as to how to dual spec your class.
Quest Tracking: The most useful and possibly most annoying thing about the improved Quest tracking features is that the item you need to use to complete a quest will be displayed and usable next to the quest on your main screen. It is very useful, when your quest is being actively tracked and if you have enough screen real estate. I find that the changes don't affect my questing very much and a program like Quest Helper still very much makes the leveling faster and more convenient.
Talent Calculator: The new built-in Talent Calculator did get implemented, but you have to activate it -- on every character. Go to the Game Menu, Interface, Display and then check the box that says Preview Talent Changes. Now, when you select your talents, you will need to accept them before they will apply. But this allows you to right click to remove any selections and make changes as needed before accepting them. I don't really find it intuitive that it is listed under Display, nor do I agree with having it default to off. But I'm happy it's there, now that I know where to find it. And since my druid was hit by the talents disappearing bug multiple times, I made good use of it.
Other little casual friendly changes did get made as promised, such as Hearthstone cooldown times getting reduced to 30 minutes (yay!) and ground mounts swimming through water instead of dismounting you (also yay!). Overall, the patches and instability and bugfixes did finally end up in a more casual friendly game for us.
Oh and Happy Mothers' Day to all of you gamer moms out there! I hope you get some extra uninterrupted playtime in today and get to see Star Trek as often as you want to. (Insert fangirl noise here)