Alright, I get what you're saying a little more now. So, in essence, you believe that, because more vocalists are getting better vocal production, you can hear less of their "personality", and therefore they are not as memorable sounding? I suppose I can see that, but it of course has a lot to do with how much stock you put into even trying to find interesting death vocalists in this day and age.
You used Covan of Decapitated as an example; I have heard Covan's vocals on Decapitated's albums with him, and he sounds fucking boring to me, exactly like you think most modern DM vocalists are impersonal sounding. So, it's definitely subjective (should be obvious), but here are some vocalists I consider to be really memorable in modern death metal.
http://www.youtube.com/watch?v=bI2oPKDuX1I
http://www.youtube.com/watch?v=OpHQdd1GY9I
http://www.youtube.com/watch?v=3XlnLMjZRlo
very excited to listen to this lot tomorrow after work. as for covan i've probably been swayed by his phenomenal stage presence.