Inconsistent labelling of difficulty is definitely a really big problem here, too.
A medium RES, a medium space CZ, a medium foot CZ, a bunch of medium-difficulty scavengers, and a signal source with a "middle of the numbers you're likely to see" threat level are so massively different in terms of challenge as to make "try it and find out" about the only practical way.
It's fine for a medium space CZ to be end-game content which gives my fully-engineered combat ship a workout (and a high one something I'd only bother with in a wing because otherwise I'll be synthesising ammo mid-fight). But they should be clearly indicated as such and not just in a "well, obviously everyone who's played for 1000 hours knows that" way.
Lack of range of size of missions is really a problem. If I want to fly a Cobra III or similar for a bit, I'm basically shut out of doing cargo missions (or at the very least, they're going to be multiple-run slogs) because every single cargo mission is approaching or above 100t at a time. Why not have some lower-paid 10t and 20t missions on the board as well - if I'm in a small ship I can take them, if I'm in a medium ship I can see if I can stack them, or take one and fill the rest of the hold from the market.
And similarly, why not have some "wing" assassination missions which are an Expert-ranked T10 and a bunch of Mostly Harmless eagles. Sure, an experienced player could walk over them alone (that's why the mission wouldn't pay very much) but a few beginners in an Asp, a Vulture and a Viper III can have a good time.