I'd support adding a scaling minimum ilvl to the roulette but there's a caveat.

How do you handle folks that hit 60/70/etc. before they've unlocked the appropriate tomestone vendor? Or even white gear vendor? Somebody who's diligent about running roulettes is going to be 60 well before they hit HW. Same with SB and ShB. Are they now doomed to the vagaries of the market board or the good will of somebody who has? Too risky IMO.

There are two ways to handle that. The first is to use the min ilvl of the highest raid a character has unlocked. The second is to not story and region gate those vendors. As an aside having all the poetics vendors in one spot would be a huge QoL feature.