I just got stomped badly by the computer in Prithviraj 5. I was able to boom until yellow attacked. It was impossible to repel the attack without a castle. I play on moderate, and I think if we are surrounded by enemies we should at least be able to defend ourselves. I googled and looks like you have to convert 3 rajas before you can build a castle, but with the ghorid raids and not being able to build a town center it seems absolutely impossible to boom prior to being attacked by yellow and green. If the castle is still off limits, at least the player should be able to build town centers. I was re playing the tutorials and the booming mission encourages building several town centers to increase your villager population fast enough. I only got the bronze medal on that one but the message was clear: booming depends on several town centers. As it stands right now it is practically impossible to survive long enough to convert the 4 rajas.
Another thing: the ghorid raiders are said to raid india, yet they focus exclusively on the player, arent the other rajas indians too? makes no sense to have them ignore the other indians in the map.