Yes, this suggestion was already proposed and the Edain Team, as I recall correctly, didn't agree. Thorin's royal armour was already an advanced improvement for the Blue Mountains, and it was too backed by a solid support from the Community; they decided, though, not to extend the usage of that kingly type of armours to the other heroes, because, I guess, this would have detached so much from the loose and unconventional essence of the faction, which doesn't/shouldn't rely so much on heavy-armoured and royal-like units and, especially, heroes (even if everything would be solely bound to Thorin's level 10 ability).
Although I always supported the smart implementation of valuable conceptual elements from the Hobbit (and those armours are valuable indeed), I feel that they could in fact alter so much the whole 'wandering and wild spirit' of the faction's heroes; and this spirit is exactly, I think, what we have come to know Thorin's Company for the most. In the end, I honestly am a bit doubtful whether this thread should remain open or not; I thus believe we had better wait for a direct response from the Edain Team, just to fully clarify all the possible doubts and to draw a defined line about this topic itself.
Thanks for the feedback, if it has been discussed before then I really want to push the idea, as we've seen with the dwarven re work, if enough people get behind an idea then the team will consider it!
Just to give a little insight and opinion of mine regarding that significant change: It's not that the Edain Team finally opted to consider the demand for an overhaul only after the people's favourable expression in threads or polls. They had always considered that suggestion very carefully, and never had they forgotten it in any way. The situation was much more complex due to the presence of many other factors involved, beside the important support from the Community.
For example, some members of the Edain Team were in favour while others weren't; the immediate implementation of those models could have not been achieved because of the daunting efforts and work needed, and we must always bear in mind that a large part of the forum didn't like the whole idea either. So, you see, it was a quite complicated ensemble of diverse variables.
That said, as part of the people who had always supported the overhaul, I'm obviously delighted that the change eventually found a way into the game. Only, speaking about your proposal and other ones as well, you should remember that the sheer number of people that might support a suggestion doesn't automatically grant you success or assure that the very idea will be implemented and accepted. The real combination for a good proposal is rather the holistic ensemble of support (which, as I wrote, is always fundamental), consistent concepts, rational intentions and a proper debate behind the whole thing.