Most people are probably using the textures that I created, and I never claimed to be the best texturer in the world
If you use OpenZone exclusively rather than in combination with an external 3D tool then you'll have some more limitations because OpenZone isn't a full-blown 3D tool in its own right but more of a zone construction set. In making OpenZone I decided to sacrifice some raw power for an easier learning curve, though OpenZone can import .3DS and .AN8 models so you can still benefit from the power of real 3D tools. You actually can make some very nice zones in OpenZone however, and my experience from seeing others' work is that results tend to improve with time and more learning.
OpenZone's generation capabilities are designed around zones up to the level of perhaps Velious, though you can do much better if you create your ground areas in another 3D tool and import from there. I've been mulling over upgrading OpenZone's ground handling for some release point before 8.0, but the work on client mob models has taken a higher priority for the time being. Still, if you're interested in making zones, I think it's better to learn all the ins and outs of OpenZone now as it can do a lot more than most people tend to use and is more complex than most people think.
WC