While I agree it's a core element of Metroid, and I completely understand how it would bother many fans, but for me this is one of the less-essential aspects of Metroid. But it's possible that much of my initial enjoyment was because I had played Metroid Fusion before that, which is much worse as a Metroid (while still fun as a game).

It could also be because I got 'hooked' on Metroid because of Metroid Prime, and IIRC that one also was a bit more linear by virtue of the hint system.