In general, on radio, looks should not make a difference. Look at the Stern show, biggest radio show ever, nobody was good looking. Well Robin was attractive....sometimes....but a lot of us never even knew what she looked like, and just listened on radio....
It's the problem with wanting to put the show on TV. Some things work on tv and don't work on radio, and vice versa. Certainly, having good looks never hurt anyone. Everything else being equal, they will always take the more attractive person. That's just nature.
I haven't heard Brent Stover very much, just a little bit. But what I did hear, and saw a bit on youtube, was nothing impressive. Maybe he will fit in okay. It's hard to judge how it would go, just off of his appearances when Nick was there. With Nick gone, the whole dynamic and vibe in that place is going to change. It's going to be totally different.
To be honest, realistically, I don't expect Artie to make it through this year, let alone his full contract. I've been listening to him long enough to know that he's just too fucked up to hold it all together. He continues to romanticize the druggy loser lifestyle like some adolescent rocker kid. When he's straight and doing well, he wishes that he wasn't. He dooms himself. I mean if somebody doesn't want to change, they why would we ever expect them to.