Will this result in people spending all of their Puissance on defence and none on developing rooms, or sharpening attacks against each other?

Maybe? I could increase the formula for how much it scales, but I think having some level of protection seems like a good thing to have.

I made it 3+2x rather than 3+1x

I think thematically, this could result in some vampire lords using all of *their* Puissance on paranoids self defense while recruiting lackies to go on the offensive for them. Which feels thematically appropriate.

My gut feel is that Vampire Lords will still generate Puissance way faster than Richardo will knock down wards; a Sepulchre with 2 wards is highly unlikely to get knocked over in one run, so this would make Sepulchres very static.

Maybe? It costs 5 Puissance to put a second Ward up. That feels a expensive enough.

Ultimately Sepulchre in the current form are very swingy. There isn’t a ton you can do but hope that Richardo doesn’t pay you a visit and basically reset everything for you. This provides some measure of counterplay against the swinginess.

I’d prefer to fix this problem by encouraging people to adapt the surrounding rooms; I think this fix is likely to lead to uninteresting gameplay. (Maybe we need a mechanic for adding features to rooms after they’ve been built.)

adding features to rooms might make it a bit too easy to simply wall yourself off and force some super expensive devastation plays to counter