Dimensioning has been drastically over-hauled in AutoCAD 2016! Starting with a new layer control, you can preset what layer you want dimensions to be located on regardless of the current layer. With the new DIMLAYER system variable you can also create a new layer to be used.
Next item drastically increases productivity in dimensioning inside AutoCAD 2016 is its built-in intelligent feature that automatically creates the appropriate dimension with a preview based on the object you are hovering over during the creation process. For example, if you start the DIM command and hover your cursor over a linear object (e.g. Line…) A preview of a horizontal, vertical or aligned dimension will display. If the display looks correct, just pick the object (e.g. line) and them pick the dimension line location. The extension lines will automatically snap to the endpoints of the object you are dimensioning. Or… after picking the first line you can then hover the cursor over another non-parallel linear object and it will automatically switch to an angular dimension, you can then pick that object then place the angular dimension. You can also force the type of dimension through the command line or the right+click shortcut menu during the process.