That is a perfect example. He sounds so 'gurgly' and not really 'old' like he use to. It's a different voice completely!
I find Schemmel suffers from this weird gurgling in their voice where it never happened before. Maybe years of screaming has damaged their voice?? I know this kind of thing happened to Dave Mustaine of Megadeth, who's voice use to be very high pitched and smooth; now, Mustaine's voice has dropped (due to age and damage) but it is also so much raspier or gravely. When he sings, it also has that weird gurgle attribute to it that was never there before (Before 1995, Mustaine seemed to have no noticeable alterations in his singing or speaking voice). I find Schemmel and McFarland have the exact same thing happening to them. I expect in a few years their voice might be completely different, like with Mustaine. There are video comparisons of Mustaine's voice where it began to change in 1995, but VERY SLOWLY changed until present day. At first he could not get the grit in his voice as well until he couldn't do that anymore when hitting higher notes. So, by the year 2000, Mustaine's could not hit the high notes with the grit at all. It remained that way until about 2009/2010. By 2010, his speaking voice changed drastically, where it became very 'gurgly' and much deeper (yet in 2008, his voice still was much smoother and higher pitched). He can't sing since 2010. He has dropped pitch in all his performances post-2010 because he can't even sing anymore.
I expect this slow burn in vocal deterioration is happening to McFarland and Schemmel and that is why they talk or scream with that gurgle when voice acting, especially in intense scenes. I'm sure a few more years down the road they will not be able to scream (like Mustaine hitting high notes with grit, and later unable to hit them at all) like they use to until they can't do it anymore. The way Schemmel screams does damage the vocal cords if done very often. Both actors pitches in their voices seem to have also dropped a bit compared to 2003, just like Dave Mustaine.
EDIT: Listening to the trailer again, Ayres screams in a way that is extremely damaging. I expect his voice to devolve like McFarland's has. It will develop a weird gurgle, lower in pitch, and he will not have the same intensity like he does now. Don't say it is aging, because singers like Shirley Bassey, who is over 70, sounds exactly like they did in their twenties. Bassey took care of her voice and has the exact same intensity, hitting all the notes identically as she did in her prime. So, I do not want to blame it on age. Drinking excessively, and smoking also causes further damage.
Actually, I just realized as I typed the edit that one DB actor is a prime example of vocal deterioration due to screaming, smoking, and overall not taking care of his voice: that actor is Ryo Horikawa!! His Vegeta has that weird gurgle when in the past it use to be so smooth. Additionally, he cannot yell like he use to (and when he does, it has that gurgle, just like Mustaine, just like McFarland, and Schemmel!!!).
Mustaine is the worst case scenario of vocal deterioration. I'd expect Schemmel and McFarland to end up like Horikawa as the years go by more so than the ultra-damaged voice of Mustaine.
My favourite art style (and animation) outside Toriyama who worked on Dragon Ball: Katsuyoshi Nakatsuru, Masaki Satō, Minoru Maeda, Takeo Ide, Hisashi Eguchi, Katsumi Aoshima, Tomekichi Takeuchi, Masahiro Shimanuki, Kazuya Hisada