I think you may have a different idea of "Difficulty" than the players.
To me, "Difficulty" is having the nether be a dangerous place. "Difficulty" isn't having it require a tedious, boring, 10-15 minute walk to get there...
No, my definition of difficult is the same as everyone else's. Having to walk there means you need planning. You need to set out with the right gear to ensure that you can a) deal with the nether and b) deal with the PVP/mobs on the way. Also it requires for you to have paid some attention and have set your home before you left so you can get back when you are done.
What you are saying- in a round about way - is you want it to be easy. Fighting and surviving in SMP is monumentally easy - travelling, planning and actually thinking: that's the hard stuff
But it's not hard. Seriously. I can get to the Nether Fortress with the starter kit. Wait until dawn when all the mobs die off, then head in a straight line to get there. It's not hard at all.
It's literally a boring 10-15 minute walk. You're making it seem like walking in a straight line for 10 minutes is an epic challenge. It's not. It's boring, it's un-engaging, and it's really needless. Hell, to show how non-difficult the journey is, I could get a few thousand cobble and build a bridge there, where mobs wouldn't even be able to touch you.
I have no clue how you think it's even remotely hard, unless you're being foolish and going out at night. If I had FRAPS working right, I'd record a video of it for you. It's literally walking/boating in a straight line.
The Nether Fortress itself, I like. It's a challenge and will DEFINITELY weed out the ones who can't handle it. It's the freaking billion mile walk to get there that I'm complaining about.