Feb 13th 2008 3:25AM Blizzard 'stole' plenty of things before the Quest Tracker, which is rather recent. Opening the loot window under the cursor? Buff timers? Auto cast-on-self without a target? Raid frames? Hunter pet auto-dash/dive? These are just a few things that came long before the quest tracker.
Would you rather prefer to require addons for each of these? Is not having to target yourself to cast buffs or heals on yourself too buggy now that it's implemented into the default UI? A large number of addons over the years have been to fix flaws or add essential things to the UI, which Blizzard have noticed and fixed. Sure some things have worked better than others when integrated, but don't think your opinion on them are the be all end all. I personally -hate- what SCT has become these days and love the integrated combat text to death. You'll notice there's also a checkbox to turn them off if you don't like them. So, do so and continue using what you prefer rather than complaining that Blizzard are stealing everyone's ideas.