To me science seems to work like you always need something off all quadrants/sectors. Cost of research also increase like it seems it’s usually beneficial to research from another sector if I have opened less technology stages from that sector. Like if I already opened stage 3 of Economy and Trade I will normally be better off opening stage 3 of other sectors before going on with Economy and Trade. (Last statement not always true, but often.) The only sector that I always choose last, and I sometimes leave lagging behind, is the Military quadrant. This is because I actually consider the other three sectors as important to the military game as the Military quadrant:

1. Empire development because of the hulls. I would prefer a larger hull/enhanced hull above a technology that gives me another module or battle cards, any time. 
2. Economy and Trade because of the resources: The enhanced versions of the hulls I consider twice as cost effective as the basic versions, but the enhanced hull slots require special resources. Having the right resources may also be critical for ship modules: For most types I have basic versions that don’t require resources to choose from, but actually it’s normal that I have one or two module types where I lack access to the basic module type, so I have to choose the special type requiring resources and/or the basic type I have access too is so old tech it’s useless.
3. Science and Exploration because of the movement modules, and because getting more science out of each system is needed. Like: I can imagine that those players who is able to complete a military victory on turn 100 at maximum difficulty must be getting sufficient science just by conquering systems, but for those who don’t know the game that well to play that fast and/or choose to play differently, taking a few systems from my nearest neighbours is not sufficient to stay level with the Sophon on the other side of the Galaxy. I actually need to keep an equal emphasis on science sector for more planets and system improvements creating science to be able to also research higher level military techs in time.

Example from my last game:

I met Craver’s early, but distance to the Cravers was that long I didn’t actually fight the Cravers until past turn 100. At that point, the Cravers had one system more than me, but probably fewer planets (I didn’t count). And the Cravers AI, which had obviously chosen military quadrant techs first, had a maxed fleet better than mine. My advantage/his problem, was I had been able to produce four maxed fleets of medium sized ships and had 12 movement points on these fleets, while he had been able to produce only one such medium sized fleet with 4 movement points on his fleet. At the same time the Cravers attack/defence values on that fleet was only something like 15% better than my attack/defence values. So obviously I was much better off. The differences in production, movement, and combat values I consider results of me focusing on on non-military research first, and the Craver AI focuses on military research first.

_ Kudos to AI-developers: I didn’t get to fight that Craver fleet, because soon after the Cravers sued for peace which I accepted. I think this was a correct evaluation of Craver AI to sue for peace: I would probably have faced a loss on my first battle with that Craver fleet, but I had full control over when the battle would take place and could make sure the Craver fleet got destroyed in a follow up attack the very same turn. And I could easily recover from a single lost fight, but the Cravers would not have recovered from loosing their first and only fleet of medium sized ships.

Now I recognise the above described desire/need to research all sectors means the science is already quite well balanced. But I still think it’s possible to improve this. I didn’t work out a solution on how to rearrange. But if I was to try my first attempt to improve would obey the following rules:

• Military quadrant: Should include basic weapon modules, command point improvements and battle cards as today, but should also include the primary hulls needed for attack: Attacker, hunter and Carrier. Support ships I would keep in Empire development, at least for first try. Some special version weapon/defence modules (requiring resources) and some support modules can be moved to other quadrants to not make military sector too bolstered.
• Empire development: The attacker, hunter and carrier moved to military quadrant should be replaced by technologies/improvements boosting industry taken from the Economy and Trade quadrant.
• Economy and trade: Don’t allow players to unlock system developments by researching market and industry techs only: Reduce the number of industry developments by moving some to Empire development quadrant and give different levels of market access as stage unlock bonuses instead of giving them away as techs!  Then both market access and system development comes as a result of researching dust, resource, trade and maybe some remaining industry technologies. Economy and trade technologies should include some (most of?) the modules removed from the Military quadrant.
  • With the anticipated upcoming Espionage addition, I would also add the majority of Espionage technologies to the Economy and Trade quadrant as well. Espionage should be considered a trade/market thing. Just consider how big corp is making a profit of collecting mass user data/big data on consumers on the Internett today. Will there be an information market place in ES2?
• Science and Exploration: More or less unchanged. Could consider if a very limited number of planet types could be moved to other sectors.

As I said. I didn’t actually create a specific solution here. This was just the guidelines I would use to create a first solution for improved balance.

I consider the above an improvement because, how I play the game the above changes would make it more relevant for me to unlock next stage for military sector sooner/first, but still keep my options open for when I go for other strategies. How I play, I win in between turn 140 and turn 180. I actually dont' know about others, but for lack of better knowledge I'd just guess that's about average for ES2 players. For people winning the game slower than me, the suggested improvements would be even more desired. For "expert players" winning the game much faster, the military sector may become too powerful with my suggestions. But if some expert players could win military even more easily with my suggestion, I would not consider that a tech tree balance issue anyway, but solve that by other means. So I'd think this is a good suggestion even after considering these play style differences.

What do you all think?