So where are the larger planes being utilised? And is there a resultant increase in passenger numbers on those routes?
Hvr, I can't answer the first part, but in respect of the latter, AJ stated that there'd been an 'increase in demand to SIN and MNL.'
MEL - SIN has overtaken SYD - SIN as the highest patronised airline route to/from Australia, although the difference isn't much each month. (That's for all airlines combined - it doesn't disclose market share.) For instance SQ has four daily flights ex MEL and one that operates on four days of the week as well. I haven't access to what it was like a decade ago but I'd bet the frequency has hugely risen.
There's been a large rise in the number of Australia to Philippines flights in the past decade, bearing in mind we have more Filipinos living here than Vietnamese. My vague recollection is that then, one would be lucky if there were 10 flights a week each way, and some of those were PR operating a MNL - SYD - MEL - MNL triangular flight, or the reverse (something that AI initially tried ex and to DEL.)
Today, although it varies by month, there's typically at least five MEL - MNL PR each week, three 5J/wk on that route, plus 5x/week BNE - MNL PR and daily PR SYD - MNL plus at least 5 QF and 4 5J, so at least, making a minimum of 29 weekly flights each way. In December/January, that will rise.