I'll repeat. The best would be the following.
171: Yishun Interchange <> Lor 1 Geylang Terminal
(replacing 961 from Beauty World)
961: Woodlands Interchange <> Beauty World
(loop) missing sector covered by DTL2, 170, 170A and
171
867: new service: CCK Interchange <> Beauty World
(loop)
67: Tampines Interchange <> Rochor Canal Road (loop).
171's route is already 34km long, and you want to introduce a
diversion to make it 7km longer?!
If 171 gets rationalised, diverting it to Clementi via Ave 6
after Beauty World would be quite helpful. Other routes may end up
being too duplicative of 176, 178, 184, 961, 970, etc. If merger is
feasible/workable, then perhaps 41 or 177.
IMO the one route that should REALLY be improved is 178. Can
just split at around Bt Panjang (or alternatively, Bt Batok), run
peak-hour HCs between Woodlands and BPJ, then convert 961 to
semi-express along Woodlands Rd.