I guess. I mean hindsight is 20/20 and the difference between a "vet" and someone who's "washed" ultimately depends on whether they won or lost. Herring basically retired after the Lesnar fight, the two additional fights came years later. Before Lesnar he was at least good enough to have an even fight vs Kongo (whatever that's worth). Still, you can't say it's a weak opponent for someone's third professional fight, it's HW so no one (except maybe prime Fedor) is perfect. Couture definitely was declined but he still was the HW champ having won the belt fair and square so I don't know.
It's fair to say Lesnar got a quick path to the title, but I still think that if it was a more legit fighter without the ugly tattoos and the embarrassing WWE career his run would be viewed as legendary, more like Pereira's run to the title is viewed today. As it is now you can't shake the feeling that Lesnar's run reflected quite poorly on MMA as a whole. I 100% rooted for both Cain and Overeem vs Lesnar but I'm trying to be unbiased in my assessment of his career.