Well,I would go with "better".
Even though there are too many changes,anime makers are trying their best to give "human feel" to those drawings,after all.
ahhh those Toonami days of looking at anime art after school lol.
Me and my friends used to practive everyday in the hopes of one day getting our art on Toonami.
But to answer your questions, I feel the quality is pretty much the same although there is a different style now with the changes to anime artwork through the years.
I think it's the animation, technological aspect that has gotten better. It allows for more details, smoother quality, better color and such. What really has improved is some of the voice acting. There is a lot more variety to it. But overall I'd have to agree with ToCool. It's more that the style has changed than the quality. There is some anime out there that's older with more impressive artwork than some of the newer ones. Work produced by Ghibili for example is still really well done even dating back to earlier stages. However, there is definitely a greater variance in style these days than back then which is interesting to see.
