It's not a manuscript authoring tool, but I thought we were talking about alternatives for 'perfect typesetting.' I don't think there's any tool that is ideal for both authoring and typesetting, but since we do have this special word 'manuscript' to describe a work that hasn't been typeset yet, maybe it is useful to continue thinking of authoring as a separate task (at least if you aspire to perfection), rather than something that needs to be done at the same time, using the same tools, as typesetting.