Opinion on Tom Araya?

Now I ain't asking about whether or not Slayer is good or if you hate them, I'm asking what you think of Tom's playing skills along with singing as well. So I've seen a few Slayer concerts (hoping they don't break up so I can see em) and Tom's riffs may seem simple compared to Flea, Geddy, and other flash bassists. I love Rush and RHCP but I think Flea and Geddy are more talented than Tom. But that's not my point, his riffs don't need to be flashy, like c'mon it's metal. Slayer is a guitar based band, and Tom's singing and playing are both aggressive but not as much as the 2 guitarists Kerry and Jeff. Tom backs up the rhythm guitar to me which makes sense and even though he may seem simple, their concerts are fast paced and wild so he definitely makes up for it in keeping up even though some people say he sucks just because you can't hear him well and he doesn't play complex riffs. I know for a fact playing and singing is hard, I do it and I understand what it's like. Think about playing something like the guitar while singing like him, sounds kinda challenging . What do you think? And does he use a pick on The Big 4?