Ok. Lets just try to deferentiate draconic set(champion set with 2 handed) thus its just a 5 pc set with 5* craftable 2 pc + the 3 pc heirloom. What is better then?
Let me help you do a more comprehensive and in-depth comparison using what can be found in the gallery.
Counting ONLY set bonuses and not bonuses on the equipments themselves,
Draconic set (6 slotsx5*) has:
+1000 ATK
+800 HP
+200 CRT
Whereas the craftable Shogun set(2 slots x 5*) + Runekeeper heirloom set (4 slots x 5*) has:
+150+525+7% ATK = 675+7%ATK
+150 DEF
+450+420 HP = 870 HP
+ 105 CRT
As you can see from here, the HP and DEF granted by the craftable+heirloom set outshines the Draconic set whereas the Draconic set gains a slight edge in an extra 100 bonus CRT. But what we are most interested in of course, is the bonus ATK. Is 675+7% better than 1000? Some simple math will help us. (1000-675)/7% = 325/7% = 4642. This means that for the 675+75 to be equal to 1000, you need a base ATK stat of at least 4642. Anything above 4642 base ATK will result in the craftable+heirloom set providing more than +1000 bonus ATK.
Now referencing back to the gallery, an Ares faith Berzerker Vincent at level 30 only has 4460 base ATK, almost there. With the maximum limit break he will have a whopping 5595 base ATK. Both Drakes at max limit break and Ares faith have about 5.4-5.5k base ATK as well. Ares Berzerker Freya at max limit break will have 6020 base ATK. In fact, Ares Berzerker Freya doesn't need any limit break (just 5*+2) to achieve 4884 base ATK. Same goes for Ares Berzerker Leah, who is at 4672 base ATK before limit breaking. The Undead Jailor at max limit break and Ares faith has 5582 base ATK, without limit breaking is 4623 base ATK, which is negligible difference from 4642.
Thus you can see that, only Berzerker Vincent requires limit break for the Craftable+Heirloom set to outshine the Draconic set. For all other Berzerkers, the 4642 base ATK requisite would be met when the hero is at the 5*+2 status. As for non-Berzerker subclasses, Warlord has only slightly less ATK (about 100?) compared to Berzerkers, so they should be pretty much similar. As for Dragoons, Freya Dragoon with Ares faith only hits 4630 base ATK before any limit breaking, so Dragoons of Freya, Leah and Undead Jailor should be similar to Berzerker Vincent in terms of how well the sets work. Dragoon Vincent may be 1 step behind in that he needs about 2 limit breaks before he can reach 4642 base ATK. Gladiators are even more behind in terms of base ATK, so you can pretty much consider any Gladiator to require limit breaking at least once before the Craftable+Heirloom set becomes better or equal to the Draconic set.