Nah, not really.

That belongs to Donkey Kong Country 2: Diddy's Kong Quest if we talking the orginal trilogy. 

Including the new titles and if going for 100/2/3% (or 200% in the latest 2).

Returns > DKC2 > Tropical Freeze > DKC3 > DKC

Not including Donkey Kong Land games cause I've never played them.

True.

My logic is just:

Why would I wanna play the hardest diffculty, only to use something to make it easy.

I seriously cant beat the normal single player.
im at the last boss. ive tried atleast 100 times and i still cannot beat him.

Let me guess, having trouble hitting his sweet spot to do damage?

If its giving you a lot of trouble, try using Dixie + items from Funky's Shop.

Also when he jumps to the background, you can farm the enemies for extra hearts if you get low before hitting him again.

i usally die at the lava part. where the platforms fall. is there even a patern or it just random? 

The pattern is seeing which lava pillars fall first.

The platform gets submerged once the lava pillar falls, so you wanna stay away from the first one that falls.

You should stick with standing on the last one that fall, and jump towards the first once they do, by then they should be landable.

I haven't reached hard mode yeat but in multiplayer I find playing as Dixie a bit difficult when alone on-screen. Her float can really screw me up, she's only good for reaching higher platforms, with Diddy I have more controll.

Once you get used to her twirl she is better than diddy in a lot of ways, but diddy still has his advantages (usually in Time Trial).