If you're below a 75 wam, you're probably not passing the min WAM needed for Big 4, and below 65 for boutiques (although arguably 70).
not true
i know heaps of people who have/havent gotten offers at all sorts of companies from big 4 to bulge bracket investment banks to boutiques. I also got a few internship offers from different places and know very well what my wam was at the time. if anything what you've said is the other way around!
I'm actually gonna type up a post on this. either when I finish up my internship which has been quite long hours or after christmas, that will give some advice on this topic.
to get big 4 management consulting, your wam should preferably be over 70. a wam over 70 and enough good shit elsewhere on your resume is enough to get you to the assessment centre, at which point your grades stop mattering and performance in interviews/case studies/assessment centres is more important. big 4 consulting is very different to alot of other commerce jobs in the fact that you can have a MASSIVE boost to your chances if you have certain relevant skills that the business use in day to day operations. for example if youre applying for certain tech-y streams in those companies and you have proficiency in the coding language they use, or the business mgmt software that they use, or the type of financial modelling that they do etc. you can get through to the assessment centre with a 65 wam and even get all the way to an internship/grad role. I know someone whose doing big 4 consulting whose wam was around 66 in feb/march this year when they applied and theyre doing an internship at one right now because they found out a certain specific proficiency/skill set that is the crux of the stream he applied for and he learnt it over last summer and chucked it on his resume. keep in mind they tested him quite rigorously on it during the case study part of the application process, but he got through.
boutiques on the other hand generally are more competitive, as they have very few spots per number of applications than some bigger companies, and they can be far far more picky with their grades. your wam should also be over 70 for these and its really hard to get one with a wam under 70 unless you've got something special they really like. i know its not management consulting but Lazard the investment bank is a great example of this. they take like 2 interns a year and sometimes
one of them will get a return offer. sound like you have a small chance? we haven't even taken into account the fact that like a thousand kids apply for it.
everyone who wants to be an investment banker from melb/monash (both campuses)/rmit/deakin/adelaide/some UWA kids who want to move/masters students from all of these etc.(omg alot of internships go to masters students but thats a story for another day) are throwing their hat in the ring
assuming 1000 applications (i talked to them at a networking event and 1000 is a good number) and 2 kids get an internship, thats already 0.2% acceptance rate which is way smaller than any of the big 4. as such, when they first get their resumes, they have to throw at least 600 in the bin immediately without thinking twice because theyre a small company and cant really waste internal resources going through it all. if you ask them what their hiring process is at a recruiting event theyll tell you that when the bankers get down time from their legit finance work they go through the resumes etc. and start to sort. (HR doesnt select for them, your future peers do). that means if your wam isnt good enough (usually 70 is the first barrier) its going in the bin. if you dont go to melbourne or monash (rmit and occasionally deakin are okay if your wam is >80), its going in the bin. only thing that can save you is if you have something that massively stands out on your resume/transcript like "did a internship in the same industry last year" or "cured cancer"or something that just screams "do not throw me in the bin".
alot of the big 4 have very good talent recruitment and can be more rigorous than that and spend a bit more time on your application but boutiques dont think twice about it.
i worked at a boutique firm in finance and did alot of work with helping recuitment, so i've seen how it works from the inside at the smaller companies.
btw im not taking a shot at anyone with this stuff

i just want to help out my fellow AN'ers who are struggling through the competitiveness of commerce. theres alot of misinformation that goes around the uni and the FBE and the internet and shit becomes like a game of chinese whispers.
also to answer the question RE: QM2 vs ecom for usefulness in management consulting. QM2 is definitely the winner. in the mgmt consulting workplace you will rarely have to do any time series analysis or do any regression that doesnt take 2 clicks in excel. you will however find a use in the hypothesis tests that you learn in qm2. ones i know that have been used in consulting by keen ex-QM2 students are particularly ANOVA, Kruskall-Wallis, & the mann-whitney(wilcoxon rank sum) test. knowing these will never be required and most of the people in the firm wont know them but you might find a use for them just so you can say "x y z is statistically significant" "our data shows that Y is clearly X" etc. etc.
in general though it doesnt really matter. you are deadse better off doing business decision analysis or market & business research if your dream si big 4 consulting.
happy hunting