Northerner Inferno Cannon - A bigger flame cannon. still does almost no damage but starts even bigger fires.
Area of effect fire creation is likely to be overpowered because fires block crew access. It would be too easy to mass electrobolts and inferno cannons and shut down any enemy not based on off-axis missiles and frontal armor.
Northerner Heavy Armor - More health and pen resistance but at a higher cost
Light Armor - Less health and pen resistance but at a lower cost
Light Shield - A cheap shield that will block most shots but less energy and regen.
Heavy Shield - An Expensive shield that will stop just about anything . has more energy and regen.
Laser AMS - A PD that is more accurate and does the same damage but less range and slower fire rate.
Heavy AMS - A PD that fires a large energy "arrow" that destroys missiles along its path.
These will tend to either be useless or make other components useless. I suspect Light Armor will only be used for decorative greebles because armor is usually volume limited. Unless the emitters are different sizes, heavy shields will render standard and light shields obsolete. I suspect LAMS and HAMS will just not work right.
Northerner Cold Fusion Reactor : An expensive but safe high yield reactor that does not explode on destruction.
I don't think there's any reasonable price point at which this will not just replace all other reactors apart from SER in low power compartments.
Northerner Bulk Thrusters - Cheap low power thrusters that are inefficient.
Advanced Thrusters - Expensive high power thrusters that are very efficient and have other bonuses.
We kind of have bulk and advanced thrusters already in small and large. I don't think these are likely to introduce new design choices, just replace existing design choices.
Thether Drive - A FTL device that requires only 2 power cells to function but is much more expensive.
FTL is never used when power consumption matters.
Northerner CASE Ammo Storage - Double storage, and price but does not explode
Cellular Ammunition Storage Equipment Ammo Storage? You might want less redundant and more descriptive terminology for this and all the other CASE parts. Does anyone outside Battletech call it CASE?
Northerner Advanced Sensor Array - Double the price and energy use but also the vision range.
Sensor arrays are already kind of useless.
FTL Jammer - An advanced device that blocks FTL travel in a zone.
The AI never uses FTL. I don't think players ever use FTL near enemies. If it blocks FTL in the entire map it will probably just be frustrating on AI ships.
In general, be careful about things looking too similar to each other, especially in blueprint mode.