Don is, was and always will be THE best TF artist that I have ever seen. That's not to say everyone else sucks or anything - it's just that Don's style and insane attention to detail is exactly how I have always wanted TF to look, and it wasn't until I seen his stuff that I even knew that kind of grown-up look was possible.
By the tone of his answers, I get the distinct impression that he was seriously overworked but underpaid & underappreciated. Sounds like both IDW and Hasbro had a very "take it or leave it" attitude with him, and certainly didn't give the attention to his designs that he undoubtedly deserved. I guess that point is more than proven with how they released his WW Megatron without the sword, and never released his WW Grimlock, WW Prowl, second WW Seeker design, G1 Shockwave, G1/WW Cosmos, WW Bumblebee/Cliffjumper, etc. at all.
I'm glad he was given the opportunity to rise from comic artist to Hasbro designer since we got a few kick ass figures out of it (WW Prime & Classics Jetfire in particular), but it's a crying shame that we won't see more of his stuff in print or in three dimensional toy form.