In DAX, combine aggregation functions with their iterator counterpart
Many of the aggregation functions in DAX come in pairs. For example, SUM and SUMX, or MIN and MINX. The "not X" functions aggregate a single column and the "X" functions evaluate an expression for each row of a table and aggregate the results.
Using SUM as an example, why not just have SUM act like both SUM and SUMX and then SUMX can be deprecated? If the 1st argument is a column name, then it should act like SUM. If the 1st argument is a table, then it should act like SUMX.
This would greatly declutter the list of functions, both now and in the future, which, in turn, makes the language less intimidating, especially for beginners. If you are worried that multiple syntaxes will cause confusion, just remember that a similar idea is already used in the ALL function.
Kenneth Barber commented