While I am sure its pretty safe to assume that the roaming primal ideas will no longer happen due to lack of information, I could not help but come up with an idea after I was chatting to my brother and well here it is.
In this example I will be using Ifrit as the roaming primal but the others too will get it.
Starting the Fight
The first part of the idea is that the Primal would need to be summoned into the world and to do this they need crystals and I thought why not have these delivered by the beast tribes across the map.
So using Ifrit as an example we could imagine that whenever someone enters South Thanalan there is a percentage chance that a beast tribe caravan will appear to said person (only that person's party can see it - not the whole server).
Read the rest at: http://lifeineorzea.com/2016/my-idea-of-roaming-primals.html
Why not have them visible to the whole server? It could be like world bosses.
Not in the beta for ARR, that I saw anyways.
Truth be told I don't know what Ifrit thinks about so I guess he could wonder about things.
might work in a fate scenario.
Crystal carts with summoners channeling power to a primal. Eliminate summoners then FATE two starts and the primal is unleashed. Power of primal can adjust by the amount of summoners killed. Work just like odin... maybe offer better rewards.
Otherwise i dont see how it would work nor why
@ Kupo Warkson - Whoops, think I forgot to write in there that the caravan bit was only solo - the actual Primal fight itself would be server wide :P