Are there same rules for Heritage armor just like as for Allied race?
Or
for example:
Can I race change my Worgen with exalted Ironforge to a Dwarf and be able to do scenario for Heritage armor or can I boost a new Dwarf, get exalted with Ironforge and then go to do a scenario?
rules are different, you just need exalthed with the corresponding faction (that you can farm easily repeating tbc dungeons with a tabard on iirc) and a 110 or 120 toon of the appropriate race, no need to have leveled it all the way from scratch
Rules are different, mostly because making them identical didn’t make sense in the eyes of Blizzard. If they would require leveling all the way from 1 to 120 then plenty of people already did that and they would just get them without even noticing for free. If they would require you to level up a whole new character that would be too much. So they settled on a rep locked questline that tells the story of your race and rewards you with the set.
What do you need to unlock heritage armor for Dwarf: Level 120 Dwarf that is exalted with Ironforge
What do you need to unlock heritage armor for Blood Elf: Level 120 Blood Elf that is exalted with Silvermoon City
Leveling isn’t a requirement.
When you race change 120 character of any race that is exalted with Ironforge into a Dwarf you will have level 120 Dwarf that is exalted with Ironforge. This matches perferctly with the requirements so you will be able to unlock that heritage armor.
When you race change 120 character of any race that is exalted with Silvermoon City into a Blood Elf you will have level 120 Blood Elf that is exalted with Silvermoon City. That matches perfectly with the requirements to unlock that heritage armor.