Yeah well.. I just recently saw it happen again in a playthrough. (it ended at the helmet)
I thought the helmet flashing white would be enough but it does not seem to be.
I'm fine with people running outside once or twice and dying (and I kinda want them to, to be honest) but when the playthroughs start ending there then we have a problem.
As for "wiggling around to find the sweet spot", maybe I need to take another look at the helmet hitbox and increase it's size a bit.
In any case, "interactable object outlines" is now a gameplay option and it is enabled by default, for now.
I mean, I haven't played Metroid 2 but I'm pretty sure it would not be higher than Super Metroid on my list. ;)
As for making your own map, this is one reason why I added placeable map markers, so you can leave clues for yourself.
You're obviously not making the actual map yourself, but it is, in a sense, part of that.