When did you go to Death Mountain, dare I say?
Really, it all depends on which order you complete the game in, and what collectibles you earn first. When I came up Death Moutain, the boulders could kill with two hits, Lynels one shot you no matter what, and you had to be on your toes as well. Regarding item usage however. I must say this, if you exploit the system, then of course you will have an easy time. The original Zeldas are painfully easy once you exploit them, see enemy patterns, ect. So the question is, what are you doing about it?
A lot of people cite A Link to the Past as difficult. Yet, it is really easy considering that you can run past nearly every enemy in the game. Same with the original LoZ.
The enemy patterns really haven't changed, it is the exact same with the original and ALttP. It's likely that you just changed, making it seem like it's a lot easier than it really is.