I've been trying to get words around this topic for awhile now. I should probably save this draft and proof it a few more times, but what the heck.
One of the complaints I see about Burners is that they don't fully emulate "real" PVP fits. Burners fly faster than they should. Ships dps AND tank AND fly fast AND have high resists.
I remember some comment from CCP that they were shooting for a balance point that would emulate a fully faction fit hull, with every module having a green icon, and max skills. I've not messed around in Pyfa to know if that's still true, but it feels like in some cases they're cheating.
The reason why the difficulty is kept high is simply this: In a real PVP encounter, you never really know what you're up against. Sure, you know who's on local, and you know that based on what the target is flying what you should expect (in big terms, like: drones or not, armor vs. shield tank, kite vs. brawling). And sure, certain groups tend to fly certain doctrines. But if you're roaming around looking for a solo fight, you really don't know what you're going to run into until you find the target on a gate and you dive in.
Unlike the real world, Burners are predictable. I know that the Burner Worm is going to orbit me under high mwd at about 40km and bombard me with missiles. I know his damage profile within a percent or two. I know that in order to beat him, I need a fast ship with good web to pin him down and take him at close range. And once I have that ship fitted out, I leave it in my hanger until the next time the Worm is offered, because the Worm never adapts to me, and never learns from the tactics I use against him.
Every time the Worm is offered, I know exactly what I'm up against, unlike the real PVP world.
So, CCP has two options: dumb the encounters down, using a lower balance point, knowing that they'll be min/maxed within a day or three by the masses(1), people will yawn and farm them, or keep the difficulty very high, to at least keep things interesting for a little while longer. They've chosen the latter, resulting in a smaller pool of people doing Burners (due to skills, percieved risk, and cost investment), but yielding maybe an overall longer lifespan of the content. It's the lesser of two evils.
On the horizon, though, is some hope. CCP has stated that they are developing dynamic/procedural PVE content. This should mean that content scales in difficulty, which would offer up these kinds of fights to a wider range of players. Instead of a fixed balance point of an arbitrary "fit" the targets will adapt. If true, and if it works out, that could be a very cool thing. It won't ever replace the true PVP experience, nor should it try, but offering a range of difficulty balance points would hopefully bring a wider audience to the content.
(1) Some will say "heck, they're min/maxed before they're on the live server!" True. But compared to the number of mission runners overall, that min/max group is relatively small. My point is if Burners were easy peasy, everyone doing lvl4s would be kicking their teeth in as part of normal farming, which kind of isn't what Burners were about.