Just to share, around 21st Jan, I called in the CS tel number provided by a forummer here (hye/gen-X/or another, forgot, sorry).

to apply for MBB-2-CC , as I'm lazy to submit/fax docs again, since I hold both Amex Gold credit card and Petronas Visa.
The lady is nice, I explain and she says will check and call back. Within <10 minutes, she calls back and says alright, can submit into system (yeahoo!

)
As usual, no response or in M2u online, and from the forums here, some who applied later than me, already got their cards approved. So last week 31/1, I called again and the same lady picked up. I asked the status and she says nothing yet, so I ask her to expedite, she says will raise it up.
Last week during CNY, both cards are listed in M2u online

Now waiting delivery.
Therefore, conclusion is, apply through phone without submit docs works (for existing MBB CC), but it takes longer time and may need you to follow up.