Knowing prices is fairly simple. The economy wasn't pure scammers and rip-off artists before free trade was removed, and it isn't after it was brought back either.
Account stealing and hacking was ALWAYS profitable. RWT never slowed down because of removing free trade, it just pissed every normal player off.
Wilderness should never have been removed because wussy little PvE'rs now just whine about it. Wilderness is supposed to be dangerous and full of awesome stuff, and it is. Revenants were a complete joke. The wildy was just opened up to noobs by making it safe.
I've been playing since around 2002. I quit mostly playing about 3 months after RS2 was released because most of what made the game fun had died.
The maturity of RS has never, and will never be good. If you want to delude yourself into thinking it improved, go for it. But you're wrong.
What free trade brings back is merchanting. You can now do things like buying bulk for cheap again. You couldn't reasonably buy bulk for cheap with trade limits. Not to mention the prices were in the automated hands of the GE. Not terrible, but annoying. It was easy for clans to warp prices as they pleased. You think that was a fairer system?
Runescape will likely see many things lower in price because people can now easily be more competitive in their sales.
Thanks to the GE, you can get a general idea what an item is worth so please don't bitch about people getting 'ripped off'. If you get ripped off, you're a moron for not checking what you're buying.
Scamming existed pretty much exclusively with lower level players. Most people past level 20 have the common sense to know when they're being scammed, so trade-limit or not it still happened quite a bit.
Oh and giving gifts and trading to alternate accounts is nice. Having to train a pures woodcutting/fishing/etc so it can earn its own living was ridiculous. I'd rather transfer over some of my amassed wealth from my main and save myself the bother.
EDIT:
and might I remind you the entire purpose of removing free trade was to combat RWT.
It failed miserably. Jagex finally reversed their flawed decision. It's about damn time.
Wildy was just a casualty since it couldn't exist in its original state without making removing free trade pointless (since RWT'rs could just die to people in the wildy instead of trading).