Are passive buffs a bad thing?

Lead Systems Designer Greg "Ghostcrawler" Street posted an interesting tweet today, in response to a question about warrior and DK buffs:

The original question was asking why Warrior and DK buffs are only five minutes in duration, referring to spells such as Horn of Winter. His original response was that these buffs also provide resources, and therefore ought to be refreshed more regularly than things like Blessing of Kings. For example, Horn of Winter grants 10 runic power on use.

So the question is whether buffs like these should be given a longer duration, or whether they should be passive altogether, like Ghostcrawler's Trueshot Aura example, or the shaman Grace of Air. While these are certainly convenient and, obviously, extremely easy to use, they do lack some flavor, some skill, and certainly some interest. Particularly as a shaman, where in the space of an expansion, we went from being able to replace just about any buff with an admittedly often slightly lesser version of our own, attached to a totem, to having just a passive buff. The old system was ridiculously complicated, but fun, and part of me misses it.

What's your take? Do you prefer active, interesting buffs that have the inconvenience of complication or a regular need to re-cast, or do you think passive buffs are the way to go? And if we all have passive buffs, why bother with buffs at all?