I love the idea too, sound interesting, I am agree with all Crassus say and i think the same.
love the market idea( one more building for all the realms )
about players from both realms i dont see what is the problem to fight: guilds(realm 2/3/4) vs guild(realm2/3/4), lots of the battles will be only for fun and glory
but if IO team made one new little map or land with interesing places where all players can dig/fight/loot/sell/buy/// and there is buildings/OP for all T, then there will be real fight for example there is outpost t4: DFA realm2 will fight with Signature realm3 for this OP
from this OP u can buy/sell/heal like a little castle
, but u will have more income because realm2/3/4 players will play there, and with this guild fights and merge market ,the competition will be more fierce.
Of course IH is not so popular game than IO and thats why our priorities are on second place, and of that I know IO team work a lot under IO gameplay.
I am sure that we, all here in this forum will get one good plan of realm2/3/4 ''merge'' and will deliver it to the IH team
Edit reason: I corrected my name...