Tempo markings and dynamic text font (the one used for modifyers, when hiding the intensity marking) are also aligned to baselines. Dynamics themselves however can be both, they appear to be aligned to the ascender but only when there are items below the staff for some reason:
My first post on this forum was actually about this. Daniel responded that this was expected behavior. Two months into Dorico this is still not what I would expect however ;). This is also not how I see p and mf aligned in practice, nor in Gould (e.g. p. 105). (I know I can group them, I just don’t get why that is necessary for dynamics that ought to be at the exact same baseline position). As I approach the stage of actually finishing my first projects in Dorico these things drive me nuts as well… I feel your pain @dan_kreider.