I'd also love to have a Sins 2.
1) Move away from an infinite economy model to a finite one (like it was in Sins beta at one point) so that attrition means something, will help with both spammy nature of the game and with deadlocks.
2) Somehow... make battles more decisive (#1 will help), it simply took too long for a large fleet to significantly hurt another large fleet.
3) Slightly smaller scale might actually be better.
Regardless, Sins 1 was fantastic and Sins 2 would have a lot to live up to!
1) Infinite economy model should stay the same. Adding rare resources for specialized technologies would be a fun way to add something to the game. The Infinite economy is critical to the appeal of the game for many, and is what differentiates it from many other RTS's. Sins isn't Sins without it. Attrition does mean something, it's your accumulated advantage, and it has real impact in the game. Your enemy being fed resources can make less important, yet if your whole team is winning in attrition the opposing team will likely lose. So, attrition works quite well!
2 and 3) solved together with one idea: Make gravity wells larger, with smaller tactical areas. Have an unseen layer of "phase space" that the players have to learn by actually moving their units through, which alters ship movement attributes, and players can research different tech for seeing this phase space, each faction having a unique view of it. This could come with an increase in automation of other empire assets, perhaps an improved empire tree, one that doesn't jump around? This increases the tactical use of movement, and if incorporated with the existing Sins movement could be quite interesting. Enemy fleets would need to scout the phase space in unknown gravity wells, or risk the bee line fleet cohesion destroying slowdowns of parts of the fleet as it rushes through.
I think with Oxide the game doesn't have to have a gimped scale, it would be fun to have the same scale yet allow for more of a "fencing" duel inside of the gravity well itself. There I think, the fun, innovation and the money will be made. This allows those with tactical focus to gain an edge over those who are more strategically focused. I'd like to see more strength in the tactical game.
The player base has had time to wrap their heads around the new types of game mechanics in Sins, so time to add even more depth, here are a few ideas:
Mobile Starbases (hey, it's me! lol). Diversified defenses, allowing for deeper defense strategies, possible defense movement mechanics. Defense and Offense are in a technological superiority contest in the real military, so a simulation of this sort of system in Sins would fit nicely if your team can do it.
Increased types of strike craft/special mission craft, like the Distant Stars Mod.
-A new ship class between frigates and cruisers that have custom abilities like the IFV unit from Red Alert 2, requiring special resources and technology(instead of infantry) to gain the required tech. Each faction having a range of specialized ships. These ships can be retrofitted quickly at low cost to have different capabilites. This would replace the somewhat hokey "Sell your old fleet to make a new one" strategy that advanced players use from time to time and is also how our modern navy works. These could potentially replace Frigates and cruisers, and this replacement could be built into the game, as players tech up they could have a fundamentally new ship and economy. This idea is something similar to different levels of AI and how you could apply that to an economy and fleet logistics. Actually feeling the outdated old fleets, and playing the transition into a new type of fleets would be really cool, and I've yet to experience this as a long time RTS player.
-Regular technology requiring either special resources to research (which are found around the map) and/or in game achievements that a player earns after doing something(a reference to my older post on this subject), which then allows them to research a new technology. Interesting ways of gathering these special resources. Each discovered artifact having a larger tech tree that can be researched to give greater depth and unique character to your civilization. Maybe players can go an artifact route from the very start of the game, discovering one nearby. Perhaps all players could start with an artifact somewhere in their home cluster of planets. Unique tech's acquired by interacting with specific enemies (left over hulks of a space battle to be salvaged by a special unit? I think YES). You could then add more unique elements to the factions by HOW they adapt the technology.
-Economy idea: Planets having large resource needs, and resource production. Your empire could run far better if you facilitate trade to some degree. Major needs and shortages for each planet, with larger than normal trade convoys that your enemies could destroy outright. You either protect them or don't, yet your empire relies on them. Perhaps this will give large, temporary and degrading loyalty boosts to the planets in question, along with a burst of credits/metal/crystal, permanent production increases, logistics/tactical increases.
-Really reaching, maybe not Sins compatible: Possible planetary assault/planetary defenses/further, detailed planetary exploitation ability, perhaps a manual explore feature allowing you to actually physically discover the artifacts. Planets are big, and could defend themselves.
Also, if you'd like to have a free tester to pour hours and hours into your janky-ish alpha/pre-alpha, i'm game. I'll make a new thread for this.