I agree, this seems like a function that should be native. In the mean time, if you are asking for how to do it, there are a few alternatives that provide some additional “mesh explode” functionality.
Mesh+ and UTO’s Mesh edit tools have explode mesh components.
There are a few examples online that describe how to do it with a scripting compnent, (various flavors out there).
Here’s a python example of one we use. (it’s not better than any of the other plug-ins out there, we just found ourselves using it quite a abit and wrapped it into our studio’s tool set).
# Explode MeshFaces into individual meshes
# By Chris Hanley
# This file is part of OTools developed by OLIN digital design group at OLIN partnership, llc
# Licenesed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Explode Mesh Faces
Provided by OTools ver xx.xx.xx
M: Meshes to Explode
F: Individual Mesh faces as Meshes
ghenv.Component.Name = "OTools_ExplodeMeshFaces"
ghenv.Component.NickName = 'O_ExplodeMesh'
ghenv.Component.Category = "OTools"
ghenv.Component.SubCategory = "5.5 | Mesh"
try: ghenv.Component.AdditionalHelpFromDocStrings = "2"
newMeshes =  #empty list to hold exploded meshes
for i in range(M.Faces.Count): # for each face in M, do something
newmesh = Rhino.Geometry.Mesh() #create mesh object for each face
newmesh.Faces.AddFace(0, 1, 2)
newmesh.Faces.AddFace(0, 1, 2, 3)
F = newMeshes