I agree with the sentiment that they should NOT attempt to retrofit functionality from EC to the Classic Client. It's simply too old.
I also agree with the sentiment that EC looks as ugly as sin incarnate. KR was as ugly as sin incarnate, and until they make EC look better, no amount of awesome UI elements or mods are going to get people to adopt it.
I also agree that they should be striving to develop only one client and get everyone on board that. That client should be EC, but they have to fix the art problems.
And for the love of Pete, SUPPORT OF THE CLASSIC CLIENT IS NOT ABOUT CHEATING! Why is this ****ing strawman argument STILL being brought up? Are people that ****ing daft that they don't think you can cheat in EC too? People can cheat in World of Warcraft, and their client is INFINITELY better, along with an INFINITELY larger budget. The REASON you don't hear a lot about cheating in EC is because far fewer people USE the damn thing. It's a lot like why you don't hear about viruses for Macs - It has nothing to do with security, and EVERYTHING to do with the fact that writing viruses for them is largely a waste of money and time when you got millions of people and businesses using Windows, with YEARS of research and documentation on how to exploit it. Pulling the plug on CC will NOT stop this - they'll just quickly adapt to the new playing field. That is a guarn-damn-tee.
No, they can't directly import art from Classic and put it in Enhanced. It's a completely different rendering engine. If they want to do this right, they have to do what Saphrieena did - Take the existing art assets, upscale them, clean and sharpen them up while preserving the palette, and use/create whatever tools would be necessary to get this new art into the pipeline.
Anything else, from a graphics standpoint, is a waste of their time.