Playing through SM64 with no blob shadows:
1) Visually, at first I questioned if SM64 even had blob shadows. I started up a new file, and during the one-minute intro, I believe I activated the code. I did not see a blob shadow.
2) The first star I went for was chain-chomps. It was tough not knowing if I was on that pole. I did eventually get it, took about two minutes. I had similar difficulty even with a blob shadow though the last time I did that star.
At this point, working on the red coins and 100 coin stars, I can say that I've only made one other mistake so far which I think a blob shadow would really help out at. That was just long jumping along the seesaw bridge and I went just over the edge at the end of it.
Bob-omb Battlefield was not that big of a deal with no blob shadow.
Whomp's Fortress though, that is big when you're jumping on the sky platforms and trying to do the owl drop. (Yes, owl drop is unnecessary, but I'm playing it without most shortcuts.)
Woaaaah, it finally came out!