Apologies is this is covered better elsewhere - you can just bash me in the head and then provide the link!
General question:
For the sake of simplicity, let's say there is only one weapon type (or perhaps your opponent is only researching one type of weapon tech, if you prefer). Is it really useful to try to counter the offensive weaponry with defense at the expense of adding offense to your ships? Is there a good rule of thumb or a formula that can suggest what balance would be optimal? It just seems to me that defense is not so useful since it comes at the expense of better offensive weaponry.
Anyone?