I think the trio won´t be as well remembered as the Ash/Misty/Brock gang (or the AG gang) BUT Dawn will probably be rembembered fondly. They did a great job with her both as a part of the group and how she interatcted with her rivals/friends. But because Brock sadly got a bit backsided the trio overall aren´t as dynamic as the earlier groups were.
On the other hand, they never did anything outright wrong, but it feels to me like I will remember this group because of their individual parts more than as a group. Not that that is wrong, I liked all three of them but I felt more that they were interacting Ash - Dawn, Ash - Brock and not as a group. Dawn was more drawn to Ash as a friend and tutor than she was to Brock.
When Ash, Misty and Brock travelled it felt great because two older trainers took care and helped (as well as teased and sometimes critizesed) the younger Ash, and when in Hoenn and Kanto (BF) it was often so that when Ash and Max did something May and Brock did something else. Or when May and Ash did something Max tied himself to Brock as a teacher in practical stuffs. Result; none was left behind but now in DP it felt like Brock was a bit left behind when Ash and Dawn did something. He had niether a Max who wanted to learn about technical and practical stuffs, or a May that he coudl calm down with when Ash and Max left for some burger- run.
Brock more or less confirmed this view in DP 190, when he sees that Ash and Dawn has clear- cut goals and that made them closer and it was something that did not include Brock.
Oh, yeah, the OI trio. Well Tracy was the good guy but he never stood ou in the long run. Of course this is due to his limited time in Ash groups, but he sure was not a bad or boring character. But it is not fair to judge him by the same standards as the others. He did not much but he only got a filler season and then guest- apperences. On the other hand, I enjoyed the OI saga because it felt nice and funny, they did much funnier stuff there in the relativly short time they spent there than in the same ammount of eps in the longer sagas. I mean, just randomly pick out the same number of eps from the longer series as the OI counted, and we don´t get much, we need the whole OS, AG and DP to get what we have in terms of character development. So while the others have better character development we have to judge Tracy and the OI trio as a case of its own.