My own speculations:
- 254 to be shortened to loop at Tuas Rd and Tuas Basin Link
(and perhaps Tuas Ave 11), skipping Tuas Cres.
- New G/W loop service from Tuas Ter to serve new bus stops
along Tuas Ave 20, Cres and Ave 7/8. Will possibly ply Pioneer Rd
and Tuas Link 4 on its way from/to Tuas Ter.
- New service(s) from Tuas Ter to cover new bus stops in Tuas
South, plying Tuas South Ave 5 (serving the bus stop near Tuas
Cres).
254 will definitely be extended and have its terminating /
looping point changed.
Given the stops(?) along Tuas Ave 12, it may be possible that
254 will be extended along there (passing by EW32 Tuas West
Road), before following 192's route via Tuas Link 4 to Tuas
Terminal. It will have to skip Tuas Ave 11.
On the other hand, 192 will now have the free rein to cross over
to Tuas Ave 12 / 11 / 18 (also serving EW32 Tuas West
Road) and Tuas South Ave 5, before further extension into Tuas
South. Given its earlier route simplification during opening of Joo
Koon Int to skip Lok Yang, this seems highly probable.
Not sure where 193 fits in here though, may not see much changes
(other than bridging places with the new MRT stations). Probably
neither will 182. In addition, there should be either one new
service or an extension / modification to 256.
At some point of time later, it could bring more numbering
coherency if 182/258 or 194/254 swapped service numbers.