This talk looks at a way to break new ground in syntactic theory by reconceptualising the principles-and-parameters approach to comparative syntax, retaining its strengths and attempting to deal with its perceived weaknesses. The central idea is to organise the parameters of Universal Grammar (UG) into hierarchies, which define the ways in which properties of individually variant categories may act in concert; this creates macroparametric effects from the combined action of many microparameters. The highest position in a hierarchy defines a macroparameter, a major typological property, lower positions define successively more local properties. Parameter-setting in language acquisition starts at the highest position as this is the simplest choice; acquirers will "move down the hierarchy" when confronted with primary linguistic data (PLD) incompatible with a high setting. Hence the hierarchies simultaneously define learning paths and typological properties. In this way, the criticism that formal comparative syntax has little to offer typological studies can potentially be answered. Lastly, a more purely theoretical component of the talk aims to show that the nature of the hierarchies is determined, not directly by UG, but by UG interacting with domain-general principles of simplicity and efficiency.