A view with ISOMETRIC flag set should deliver a nice 2D view of 3D stuff when setup correctly.

See Joozey's Key Perilous as example. It uses the ISOMETRIC flag to fake a 2.5d isoemtric landscape. Full 2d is just a different viewing angle.

==> It should be no problem to use 3d and all advantages the engine gives us this way without losing the possibility to have 2d look.