Points to Patterns
It would be good to consolidate the element 'placement' or 'arraying' logic so that the maximum amount of 'cross-tool' functionality can be leveraged from each of the separate toolboxes. Placing Points grew mainly out of 2d work, but in today's 3d world, we have to cater to placing more 3d content, like Cells.
It would be good to have a tool bar for Matrix-based arrays, including Shape-based matrix arrays that are trimmed (Pattern Area). Together with the point and linear placement toolbars, it should be pretty clear to the user where the appropriate tool can be found... quickly.

Place Active Cell Matrix (why no polar or along path?)
Construct Array (also has a polar option)
Populate in Area
Array Feature (also has a polar option)
Pattern Area

The arraying tool's Settings dialog should also include a rotation input with the option to use:

A CS based on i. View CS ii. Active ACS iii. Named ACS including the global model ACS iv. Saved View.
When along path is used, there should be an option for the rotation to be based on the tangent line from the point along the curve.
When in 3d, there needs to be a way to map the cell's x,y,z CS to the array's CS. The current logic relies on 'flat' 2d pasting workflow that has the z axis being common.
A lot more could be done to support 3d workflows. Most of these tools are oriented to 2d workflows. Placing cells in 3d using the Points toolbox, Linear Pattern doesn't seem to recognise the active ACS.
Scale: The Tool's Settings dialog should also have options for x,y,z scaling to 'fit' a cell to seamlessly tile a plane or linear array (like the way Linestyles and Linear Pattern's complete cycle option).
Offset: The Tool should have standard settings for an Offset in the x,y,z as well as normal/perpendicular directions. The pipe command should be recognised to allow multiple offsets.
Distance: along a path should recognise T-parameter style fractions, PCS' Array Along Path options.

Distance input should also recognise multiple spacings that would repeat. '2,1,3-DF,DF,H' would repeat the element with a cycle of 2m.. 1m.. 3m, drop the first and last element and centre the array along the path.
The Place Active Cell Matrix tool should have the option in the dialog to place the cells as Shared Cells.
The Manipulate Element toolbox's Construct Array and Array Along Path tool should have an option to generate the arrayed elements as Cells or Shared Cells. The user would be prompted to tentative to a point for the generated cell's origin.
The Pattern Area tool should be able to handle 3d cells. I think this was in at one point but then omitted from Mstn.
The Populate tool should have an option to array cells using the placement logic used by the Points and Patterns toolboxes, not just at random. The Populate tool's alignment option would be a good starting point to provide the means to pattern 3d surfaces/meshes.Viz's geometry maps / UV mapping from Modo?
There should be a standard tool setting to gather arrayed elements/cells as a graphic group or orphan cell. This is a useful simple way to manage the ever increasing number of elements that come with 3d and BIM working. The result of an array shouldn't be a bunch of loose elements. We need the option to at least re-select the elements as a group.