corvettes basicly already have their own armor type.
its only shared currently with fighters, which, only take damage from other fighters and flack frigs...
so medium-titan modifiers are totally touchable without affecting previous balance.
This is true, but adjusting the damage they take would be a difficult way to balance them. When microed they avoid most damage by exploiting frigate's slow turn speed(always attacking from behind), meaning even with a damage boost it would be difficult to make any specific type of frigate a counter for them.
Moreover they are suppose to counter capitalships, so their capital-ship armor value shouldn't be increased above the current 25%.
The changes we likely want are:
A). make them more counterably by flak
B ). make them not shred pretty much everything fast. They should be great at killing scouts & LRF, good at killing Cap-ships, and have a slight advantage against LF only due to their maneuverability. But they shouldn't be any good at killing other frigates.
Accomplishing A by chancing armor values would hurt fighters as well and frankyl B may only be addressed via corvette damage. This is not to say both A & B need to be implemented, but the point is neither can really be achieved by changing the armor type corvettes & fighters use.