Honestly, I haven't seen either Last House or Elm Street in years and years, but they've become my nostalgia picks - films that made such an impression on me at the time I first watched them, that I can't bring myself to downgrade them regardless of my current skepticism and world-weariness. Elm Street scared the sh!t out of me as a kid, and again at 14 or 15 when I watched the first 3 in a row as part of some Halloween marathon on TV. It probably wouldn't have anywhere near the same impact now, but it doesn't matter. It's already one of those movies I've made up my mind I like no matter what. Kind of like Star Wars, which hit me with such a sense of joy and wonder when I saw it at 7 years old, that even my last rewatch, which proved to be disappointingly dull, could not unsettle it as one of those special memories unaffected by the ravages of time on my psyche.
The Last House was just unusually disturbed and dread-inducing. I found it a genuinely harrowing experience and appreciated the way it unsettled me. Very few movies make me feel anything at all, so I'm lenient on those that manage to shake me up in some way, even if the feelings they inspire are little more than discomfort and disgust. On the whole, it wouldn't have had anywhere near the impact with a glossy look, so I think even the crude aesthetic worked in its favour.
As for Scream, I found it rather clever in the sense that it managed to function as a cheeky, almost comedic meta-commentary on the genre, as well as a surprisingly effective horror film in its own right. I thought the first killing was quite intense, and the whole thing was just a lot of fun in general.
Check out New Nightmare, btw. It seems a shame that you watched most Elm Street installments, but gave up before the one that kinda deconstructs the whole series in a relatively thoughtful way. It's not a great film, but it is an interesting one.

I think I'll need to see The Last House again - it was my first Craven back in 2010 and had a real raw, disturbing power despite the mega-crude aesthetic that counted as a slight plus as well as a fat minus if that makes any sense (well, decent acting has never hurt a motion picture). As for Elm Street & Scream, that's just cheese. Fun in places, but never genuinely scary or whatever they're supposed to be like.
"facts are stupid things" Ronald Reagan

1. The Last House on the Left 8/10
2. A Nightmare on Elm Street 8/10
3. Scream 7/10
4. New Nightmare 7/10
5. The Hills Have Eyes 6/10
6. The People Under the Stairs 5/10

1. The Last House On The Left 6,5/10
2. The Serpent And The Rainbow 6,5/10
3. Red Eye 6/10
4. The Hills Have Eyes 6/10
5. Nightmare On Elm Street 6/10
6. Scream 5,5/10
   "facts are stupid things" Ronald Reagan

I always thought it was just 'Shocker'
Top 5.
5. The Hills Have Eyes
4. Red Eye
3.The People Under The Stairs
2. Scream

1. A Nightmare On Elm Street

Scream & Nightmare