Shorter range and quicker landing nuke option. Regional conflicts seem to have stalemated nukes are under powered and the delay makes them less useful except in the longest of sieges.

A shorter range option would be useful one with a quicker delay would be useful for base defense or offense.

2 ideas:

cruise missile - Can attack non claimed rooms. This could be used for strikes on enemy reserved rooms dealing enough damage to destroy containers, roads and standing creeps. Limited strike size 2-3 tile range.

artillery - Similar to cruise missile but 2 tick delay only from fire to landing. This would make it ideal for defending against incoming creeps when coupled with observers at range of 2-3 rooms.

I think there are already a lot of offensive/defensive options which have been left unexplored by players. I honestly don't believe the game is lacking when it comes to the options available in terms of mechanics.

Not to mention that power creeps will likely add a radical level of complexity and balancing problems to end game combat.

The "stalemate" is not just on regional conflicts but on conflicts in general. The real problem isn't the lack of offensive or defensive options. The real problem is the lack of motivation to fight. The vast majority of the game community has little reason to invest the significant energy required for high level combat.

There are a large number of potential military strategies that nobody has bothered to implement. Bonzai had developed some pretty cool tactics in SWW2 and he was just scratching the surface of what could be done.

Either competition over space becomes a thing again (I doubt the devs will push for this) or some other reward for combat is made available. I think a separate ranking for warfare would probably provide motivation to many of us to build advanced military tactics.