I really really doubt that. And it's a weak argument to say that because they merge the subjects into one it makes it any harder than taking two separate subjects. I had some bioengineering major students from biomedicine in my subjects in undergrad who were considering engineering as a back-up to med. None of them did particularly well and they were pretty average in assignment work, so I can't picture that they somehow 'change' when taking biomed subjects.
I don't know whether it's actually harder, but I would say that it's a lot of work nonetheless, because with a subject like BIOM20001 they go through biochemistry, genetics, cell biology, immunology and microbiology and pathology in one where they have relatively few lectures each, making the course dense. They often do not finish their lectures, hence adding a 7th lecture for the week.
They need to get their material done in that short time because it is meant to set you up with the grounding for any of those pathways you choose, like how the 2 weeks of Immunology/Microbiology we did was meant to set us up for the second semester subject Microbes in contrast with the first semester subject Principles of Microbiology Immunology for science students. I would personally have preferred the semester long subject, because it would have been more concentrated on one field, but I felt that at the same time having a grounding of all these topics alongside direct integration of the information presented and tested (half of the exam was integrated knowledge in these fields) was quite useful despite 'only' being a second year subject (most biomed lecturers from first, second and third year once in a while hold a meeting or something discussing what and how they will present information etc).
Anyway, I do not know too much about all of this stuff, and I am open to discussions or refutations.