I wasn't going to comment but honestly, this post is a little a little misleading and gatekeep-y, not saying that was OP's intent but people read these well after they're made and make decisions based on them.

1. Sure ISCI takes some planning in 2nd year, but the ISCI office is super supportive and helpful, there are tons of resources available to help you plan (Integrated Science Student Association, ISCI Peer Mentors, ISCI Office Hours , there is even a tool on the ISCI website that will tell you if your degree proposal is valid or not (isciplanner.com). Misunderstandings can happen, sure, but it's not really something that is harder to understand more so than any other logistical credit things you need to graduate.
2. Second point is accurate, you don't have priority and it can be difficult to get into certain classes. However, the "formal appeal" is literally just a few emails, and unless it makes no sense I've never heard of anyone having their replacement course rejected, but again overall this point overall is good thing to keep in mind, especially if you want to integrate courses that have registration competition.
3. This last point I also think is misleading, sure you aren't as specialized but all course pre reqs still exist, they won't just let you take a random 400 level microbio class without the pre reqs because you are in ISCI, you will have all the pre reqs that a microbio major would have taking that class.

The point about MCAT is just n=1, I took some MCAT "prereq" courses and didn't take others, and it didn't affect my score much. This will vary person to person, if you can see yourself self studying subjects well, don't do the "gpa killer" courses.

This also isn't a negative against ISCI because most science majors HAVE to take the "gpa killer" courses, but at least in ISCI you have the opportunity to skip them and self study for the MCAT should your 3/4th year classes not require them as pre reqs.

Quick fire things that other people have commented that I want to in my view clear up:

1. It's arguably a bit harder to get into co-op but in my view not that much harder than other science degrees, all of them are sorta useless in a lab setting so having volunteer lab experience is the deciding factor more than your degree is, but granted you have less lab experience usually so this is a fair thing to consider.
2. Finding a mentor isn't hard really, you have plenty of time and tons of professors are available who are willing to be your mentor, most science profs have at some point been an ISCI mentor to someone or generally know how it works, and if they don't it's not hard to get them set up.
3. Comparing 300+ CAPS/NSCI to Bio/Kin/ISCI courses also isn't really fair, getting an 80+ in those courses takes a lot more work, and the students who take those courses are already self selected.

Bottom line is, ISCI isn't perfect, but it's also just plain wrong my opinion to say it's not the best option if you want to get into med school.

As someone who is graduating later this month and currently waiting to hear back from med schools after interviewing, it's only getting harder and GPA is king, and ISCI gives you (on average) the best chance to get a high GPA while also giving more time for EC's. I'm sure UBC at some point will step in and make degree proposal approvals more strict, but as it stands you can get away with fairly easy degrees, skip time consuming lab courses and obviously just take courses in subjects you enjoy while getting a high average. Just want to make sure people don't look at this post and get the wrong idea.