Well, I was serious about opening up capital ship abilities. As you say a capital ship that can affect a titan is balanced by the fact it can be easily killed late game. I don't see the issue with adding more anti-titan options to the game. In fact Vasari already had some of this capability with the Vasari Egg being able to stop a Titan from phase jumping.
Here's my thoughts on your #'d points...
- Nerf all AoE hard
I tend to agree with this statement. The general problem with AOE damage is they tend to cause more damage due to the Shield Mitigation mechanic in the game. Abilities like Chastic Burst, Scattershot, Explosive Shot, Missile Barrage, Meteor Strike all have the potential to hit infinite targets at minimum mitigation.
I have ideas how the abilities could be rebalanced/tweaked slightly but maintain their flavor. I just don't think any changes are forthcoming so don't care to throw out ideas anymore.
- Nerf HP/armor increase with level
I don't know... Seems the AOE thing is a bigger issue.
- Titans should lose XP on death
My idea was Titans would lose XP on death but could be purchased up to previous level after it was built. Basically you'd get the purchase level button like for capital ships. This would give players time to take out a newly constructed titan before it could finish purchasing it's previous levels. Plus the level purchase would take quite a bit of time and resources if it was high level when it died.
Not going to happen as they chose to implement an upfront cost increase on rebuilds.
- Titans should only be built on volc/ice/desert/terran planets designated as capital
Don't see much point in this one.
- Shift titan role from AoE/damage to buffing/debuffing fleets.
In a manner of speaking I'm ok with this philosophy. This can actually be done with the current AOE set by toning down their damage and emphasizing the secondary effect or adding one if not present. Another option is adding target caps for things like Maw or nano leach.