I agree with what some others have said about using the new art for Towers and old art for Pillars. I think what's great about the old art is the similar style across all the Pillar designs. So I think only one style should be used for the new design, not all these new graphics.
With the new art, I like the style used for Entropy, Death#2, Water, Light, Air, and Darkness#3 better than the style used for Aether, Darkness#2, Fire, Life, Earth, Gravity, Death#3. The second set seems to be really trying to epitomize the element in a somewhat more abstract form whereas the first set is more obviously pillars but with an environment that reflects the element it represents. And since these are pillar/tower cards, I think the graphic should resemble something that could be recognized as a pillar/tower.