The latest update unfortunately doesn’t seem to have addressed Mission 7 in any meaningful way. Purple can at least hold their own now for a while, but eventually they run out of resources and can’t defend against a single ram. Gray and Red are the issue with this objective, not Purple/Blue. They need to send less, have a much lower pop cap, and become increasingly difficult as the mission goes on instead of just letting the regular AI decide what and where to send. It takes longer than 10-15 mins to complete any side objective because of how low your resources are and how long it takes to build up enough forces to handle the camps, but Gray and Red’s deathball is unstoppable by 15-20 mins, and side objectives do nothing to recover from this state.
I think red/gray should just be entirely scripted, and yellow/cyan needs to be set up so they don’t wander too far from their defensive positions. With scripting the attacks, you can much more carefully manage how long the defense will hold in each state, and it should give you the ability to make the side objectives effect the waves in some way (for instance, each depot could remove some upgrades from red/gray, but since yellow/cyan can’t (and shouldn’t) replenish eventually they will get overrun even if all they can send is battering rams and militia - not that I’m suggesting they get demoted that far, heh). Removing blue should only have the benefit that now purple can actually help cyan defend, I don’t think there’s any need to have that also upgrade purple/cyan/yellow. Purple should also have infinite resources, they are already handicapped by only having like three military buildings so why do they also have resources that run out rendering them useless, other than wanting to make them rely on you (the player) to fund them, which is just an additional thing you can’t afford until 20+ mins have passed.
All the other missions should be entirely doable on Hard (I golded all of ‘em), at least in the state they were on launch, so any additional changes made should have helped those ones… except mission 7, which is still impossible in its current state.
EDIT: also, the shipyard objective does literally nothing for purple. Red barely attacks them any more, so there’s no reason to ever do it other than using the buildings to farm Henry’s upgrades, but you won’t be able to make any meaningful use of the upgrades before it’s too late.
As of the 1/3 update, this mission now appears to be possible on Hard. It is still difficult, but it’s at least no longer impossible, and you can get a deathball going that can destroy red completely which is a bonus. Cyan can survive into about 25-30 mins without intervention, and if you’re going for the full completion strategy (all secondaries + all enemies killed) like I do, you will want to quickly get the docks freed, blow up the bridge & build a few war galleys to destroy the gunpowder depot from a distance (thankfully it’s just outside of the range of the BBT). You will need to micro the guys at the docks to do it without losing too many units (use archers/skirms to take out the cannoneers) early on, and just use pikes + TTK to get the cavalry guys. Farm Henry’s upgrades on the dock buildings, then tech into building BBCs and maxing out your pop with chunky units to take down blue before they overrun purple. I used 4 BBCs with a mix of gunpowder and cavalier + ttk which seemed to be enough. With blue out of the way, send purple to help cyan, fully upgrade your cavs and send everything to cyan to wipe out the red/cyan deathball, sniping their trebs first.
At this point it’s pretty much game, so you can take your time. I don’t think it’s possible to save all 3 castles but I’m sure somebody could do it - I managed to save 2, at least.