Personally, I feel like Culture is important but not important enough yet. It's just another thing to get, but not something which feels like a vital strategic decision. Why is this? Should it be?
I dont think (though im not sure) that culture will be changed, but balanced more yes.
I like the way it is now, it also add another option into the strategy. Will you rush with 3 civ lab's and culture spam? or will you go more military?
Also by this, depending on how fast the enemy gets it, you can sorta tell what he has done, and if you were going military you will have the upper hand (maybe as there are so many variables).
What I mean by this, is simply... He with the most, wins.
thats not true at all

its more like "He who is the smarter tactical player wins", but ofcourse if the enemy has 10 planets and you have 2, you will properly lose.
Although there are systems in place to deal with players getting a slight upperhand which results it being impossible for other players to fight back, while they are slowly annihilated... (which is not fun, by the way.) I personally don't see it as being enough, since I've seen it as being an issue that as soon as you start winning, you never stop. And as soon as someone starts being you, it's incredibly hard to stop them from winning.
Again its about tactics. You gotta know when to hit and when NOT to hit, and where

How can you turn a battle around? Should there be more ways for you to covertly cripple an enemy? The bigger they are, the harder they fall, is this true in Sins?
If its a FFA game, go diplomacy

tell a player you will pay him for attacking another. And when he does, you attack him

not that i have tried it...

Strategic Branches, this goes back to my Culture feedback. I just don't feel that there is really much option in Sins, except to go for full battle. I thought you could somehow avoid that and go for a more "pay-someone-else-to-do-the-dirty-work" approach. Or perhaps even go for pure tech and use your tech advantage to win the battles.
There are options to do so, depending on the players (enemy's) ofcourse. Id say watch some replay's and learn from them. Especially
this one where one player actually pays a player twice to help him, but gets tricked. A funny game IMO

At the moment, it seems that research money is better spent on ships and increasing the bounty on an enemy is over-rated. Is this true? What do you guys think?
not true, it depends on your play stile. Just 5% extra damage in the beginning can mean alot if you meet an equal fleet. Or if you want better ships like the small carrier whice is great if you meet someone with alot of LRM's.
I'd just like to see more ways for a person who goes for empire rather than military, to defend themselves and win the battle, without concentrating on overwhelming the enemy with more ships.
I actually beat 2 enemy fleets at the same size of my own, so i was out numbered 2 to 1. Tough both of them were enemy's to each other but didnt fight so i took one out after the other and I came out as the winner of the battle because i was the smarter one

So in my honest opinion Sins at its current stage allows alot of tactical options, and the best way to get better if you feel stuck is to watch other peeps replay's as you might learn a few tricks here and there. I did