Our 'Julia's Rose', growing in a warm - hot climate, sounds just like your descriptions. It's budded onto Fortuniana, which will often help with vigour, but this rose is not what I'd call a garden-worthy rose. It's not unhealthy, but quite sparse and spindly.
I think you're right about the brown/violet roses.
One for the cutting bed with the other ones we grow for the blooms and forgive the shortcomings of the bush?
I wonder if anyone can report a vigorous, well foliated plant of 'Julia's Rose'.

I do agree that the brown/russet/violet roses seem to be poorer growers on their own roots. Most all of them I have grown seem to need a good rootstock under them. The one exception is the Terracotta HT that is a sport of the HT florist rose Leonidas. My Terracotta's and one other I have seen in person grow quite well on their own roots with no problem, including being very winter hardy with no added help from me in my zone 5b/6a area. I also grow Leonidas and I almost cannot believe that Terracotta is a sport of that bush. Terracotta is ten times the plant and rose that Leonidas has ever hoped to be. Terracotta is more vigorous, winter hardy, heavier blooming, has better flowers, denser foliaged, and way more disease resistant than Leonidas is. There is just no comparison between the two for me. It is a shame because I think when people see Terracotta is a sport of Leonidas they assume it is very like the parent except for the color which it is not in any way. Even the petal pigmentation is much better on Terracotta than Leonidas. And, Terracotta will set OP hips and I have never had any luck at all trying Leonidas as a pollen or seed parent either one. In short, I just have a hard time believing that Terracotta is a sport of Leonidas because there are way too many differences 'tween the two.
But, most of the brown/russet/coffee/lavender roses just aren't good doers on their own roots. Of course we shouldn't forget the brown floribunda Hot Cocoa of course. It too grows well own-root or budded either one and it seems to pass that vigor to it's offspring. I have seen some gorgeous huge bushes of Hot Cocoa that were own-root that were better than those budded onto multiflora or even fortuniana.
I have heard of using Pink Clouds as an understock but haven't seen any in person. I think I might try to purchase a couple of plants of Pink Clouds and give it a try myself.