Personally I'm very much in favour of increasing players' ability to interact with each other more. It is quite easy for the game to be two people playing simultaneous solitaire.
However I also feel that interaction shouldn't be too powerful. For example, my regular opponent runs a
deck almost exclusively. I could stock my deck with Incoming Message: Federation cards and lock him out of every mission that doesn't have a facility for most of the game. I don't do that as that wouldn't be fun for either of us. If I were attending an event where I would expect to face decks from every affiliation, I wouldn't use Incoming Message as it is too narrow in its focus.
Interaction cards should not be able to affect an entire ship and crew, potentially across multiple turns IMHO. Stopping/relocating a few key personnel, or bouncing a card back to a player's hand feels like enough power with the cost of a single Interrupt card. They should also have the potential for use against every affiliation/deck under the right circumstances.
As an example, Thine Own Self is about the right level for me. It can stop any opponent from redshirting dilemmas but it isn't going to prevent them from winning if I have 20 copies in my draw deck. I'm trading one card for 1 or 2 (probably expendable) personnel, and maybe forcing my opponent to run into a serious dilemma combo with no way to avoid it.
If the CC wants to ramp up the power a little, they can do so by having the interaction card cost you a card play (e.g. an event card), a card draw, or even deducting points from your total for the truly powerful pieces. There is a lot of design space available I feel, but balancing things is a top priority.
That's my
anyway.