Software Architecture is a notoriously nebulous concept, and in my opinion what it is is in practice is largely dependent on the organizations and people involved. A description I'm fond of which I first heard from Martin Fowler at the inaugural O'Reilly Software Architecture Conferences is that architecture are the pieces that are hard to change and the role of a good architect was to destroy architecture (i.e. enable easier change).

I have spent time in an organization with ivory tower architecture, but I'm certainly in the camp that considers this a terrible model and will therefore not discuss that approach in any depth. Architecture should be a collaborative process open to all of the owners of the system (and certainly decisions should be made or approved by those who are expected to live with the consequences). I have come to appreciate that there may be a clear line between "engineering" and "architecture" where the former may entail applying an "engineering mind" to crafting solutions to provided goals whereas the latter is more concerned with working through what some of those goals are and explaining (ideally falsifiably) the rationale behind many of those decisions. Balancing trade-offs and architectural characteristics within different quanta are architectural concerns whereas engineering is building and optimizing systems within those parameters. Crucially however, these disciplines do not necessitate different roles, are likely to be tightly interwoven, and there can be massive benefits when they are both done by the same people. I have come to appreciate the fact that they involve different mindsets however and there are engineers who do not architect but those that do should be empowered to do so (and per the earlier ownership comment any archiecture without coordinated engineering buy-in is an invitation for many types of issues).

Additionally, architecture involves preserving the "conceptual integrity" (Brooks) of larger systems. In addition to needing to mediate potential disagreements between different actors, having a clear and coherent vision can chart a clearer course for the whole solution and help combat complexity that could be introduced by wanton divergence.

ATAM provides an interesting framework to tease out desired characteristics/qualities and calibrating the sensitivity of different decisions based on stakeholder needs. It is something I'll likely look to draw on a bit (I can likely benefit from more frameworks) in addition to some more recent, lighter weight approaches.