Subs and Lancers, so far as I know, are intended to have defence penalties.
It should be easy to remove if not intend and besides that subs shouldn't have two of them hitting.
Ironclad probably has a phantom promotion from promotion conversion of a few that were eliminated plus the new promotion for capital ships.
A requirement on stables wouldn't really limit most cities anyway (and doesn't sound like the easiest solution here). I agree it doesn't make more obvious sense in many cities to build them, but not all players rely on buying units. I find buying the buildings is more useful in most instances for example, as they can provide immediate benefits to a city in yields and are reasonably cheaper per production to rush. A unit only provides immediate benefits if I need to fight a war right now AND costs more to maintain than the building will. I really don't see why I'd want to rush-buy them that often.
It should be easy to remove if not intend and besides that subs shouldn't have two of them hitting.
Ironclad probably has a phantom promotion from promotion conversion of a few that were eliminated plus the new promotion for capital ships.
A requirement on stables wouldn't really limit most cities anyway (and doesn't sound like the easiest solution here). I agree it doesn't make more obvious sense in many cities to build them, but not all players rely on buying units. I find buying the buildings is more useful in most instances for example, as they can provide immediate benefits to a city in yields and are reasonably cheaper per production to rush. A unit only provides immediate benefits if I need to fight a war right now AND costs more to maintain than the building will. I really don't see why I'd want to rush-buy them that often.