I think DC was absolutely championship material, but just not up there with Hakkinen and Schumacher. If you look at 1995/1996 and are super critical about it, it tells a story.
1995, DC regularly out preformed Damon Hill. Out qualified him. Out raced him. And when you take out wheel bearing and gearbox failures, he scored more points than him too. He made some daft errors, but no more than Damon did. Damon went on to win the title in 1996, but had McLaren not taken up the DC option, there's a significant chance that Damon would've lost that title. He won because Schumacher went off to Ferrari and blew up engines on formation laps, DC was off at McLaren, Mika wasn't quite ready yet, and JV was a rookie. And even then he still almost lost.
DC is not a name you can mention alongside Hakkinen and Schumacher. But he is a name you can mention with Hill and Villeneueve. Some drivers get their titles. And some drivers, like DC and Webber, are not in the right place at the right time. I'd say Hill and JV were tier 2 champions, and DC and Webber were potential T2 champions but the stars never aligned.
And then there's the mad facts that Massa and Irvine almost won titles. If they had titles and Webber did not then that'd be crazy to think about.
I rate DC, he deserved his career in F1 and agree he’s probably a tier 2 driver alongside Hill, and crazy Jacques. I liked Hill as he came to F1 really late in his early 30’s from bikes and very nearly won the title in his 3rd season. It was kind of like a sprinter being 2 metres from the finish and someone stepping out and punching him in the face to stop him winning. I think Hill was underrated. He was no Graham, but very fast and consistent by 1995. Alesi was another one of these drivers who was very very good, but made the wrong choices when choosing a team. If you could choose the right time to move to a team when they are about to experience a downturn, Alesi would be the champion I think lol. DC and Webber are very similar I agree. Could have done it if they hadn’t been paired with better teammates at the time.