When sending art elements from Adobe Illustrator to CorelDRAW I typically save it in Illustrator 8 legacy format. I usually have various elements organized on their own layers, which Corel will preserve.
One annoying glitch I see when sending .AI artwork to CorelDRAW: compound paths will often have a pair of overlapped anchor points stacked on top each other, such as the inside counter of a letter "O." If I release the compound in Illustrator before saving and then combine the paths in CorelDRAW the glitch doesn't appear. It's a minor thing, but I still find it annoying. It can be an issue when routing sign parts, like the back of a channel letter. I just like clean paths.
I also wish CorelDRAW and Adobe Illustrator could treat each other's gradients more accurately. Both have their own interactive gradient tools. Yet neither properly understands how to import the rival's interactive gradient.
When sending artwork from CorelDRAW to Adobe Illustrator I usually just save the file down to CDR 9 format and then have Illustrator open it. Glitches that can occur: Pantone colors changed to black, goofed up gradients and text blocks with really odd line spacing.