I'm sorry I mentioned it guys, please read back to my posting, I'm talking about GAME effects, +2 tech advantage, what does it mean in a tactical game?
Since the basic premise of Traveller ship combat is physics based, with limited handwavium, you need to define what got better with Tech + 2, how those manifest in the physical world (i.e. armor gets more tough for the same weight, sensors get better resolution through betters materials or better computing power, etc.)
Gigawatt heat ,,, what about SOL level heat, did you know that at distances over 10 LY SOL is effectively invisible. There HAS to be some distance such that the photon flux from your gigawatt waste heat is just not detected at levels above background radiation. No handwavium involved, just math.
That's all well and good, but based on the math we've all seen, none of that matter at ranges that are considered tactical.
Also consider, that Traveller does have stealth -- practically perfect stealth. It's called a Jump drive. Using a Jump drive, a ship can achieve strategic, and, possibly, tactical surprise, as they just appear out of nowhere. What they can't do is gather intelligence and lie in wait. When they arrive, they arrive blind.
Time Scale: If you are in tactical combat a lot can happen in 6 seconds, as missiles are doing their closest approach and are trying to point their lazing rod array at a ship some 15,000 Km away umm that's 1/20 of a second right there, with 2X that time + fire control delay + actuator delay, your missile may have to predict where the target will be .25 seconds in the future. The missiles that have 30,000 km range will need .35 second predictions given the same level of technology in the fire control and actuator 10 hex, .3 million KM laser shots will need to predict target location at about 2 seconds in the future.
And the 80 hex, shots are predicting at 16 seconds. I would wager that target evasion makes shots at this range impossible level difficulty.
Save that nobody models ship to ship combat at the timescale (well, SFB does -- but, that's meaningless). Turns typically are 20-30 minutes. But that doesn't remove the realities of light speed weapons, and the innate difficulty of evading them as ranges close. The inherent limits manifest through accuracy of detection, accuracy of the mount, and power of the weapon. Back to the TL discussion above, as TL increases, the sensors will get better (giving a better, more accurate plot of the targets location and vector), the mounts will get better (providing higher resolution necessary to make the micro-arcsecond changes necessary to hit targets at long ranges), and weapon power.
TNE discusses the limitations of lasers and how the power is applied related to mirror size, and leaps to gravitic focusing to make lasers "useful" in ship combat without carting around mirrors that are 30 meters in diameter. It's "reasonable" to project that if they can control gravity to make enhanced lenses for focusing, they can also apply the same tech to make minor changes to the field to handle the very fine, micro arc second adjustments necessary to hit targets at range, vs some mechanical technique.
So there you have some granularity as to the usefulness of direct fire energy weapons (light speed ones that is) This includes all forms of spinal weaponry.
Generally without some special circumstances, direct fire weapons will just not be hitting beyond 10 light second ranges. We should define the range at which direct fire weapons are likely to hit to be short range, and the intermediate range where they are unlikely to hit, but still fired to be medium range, and the further range which direct fire weapons have no chance is long range.
TNE already does this. I imagine Striker does as well.
So Manned craft can do something like 8 g's without knocking out the crew, depending on tech level you can get a reasonable missile or drone that can do 60 g's, 36 Km per second added every minute 10 min of thrust gives it a vector of .1 light second every second or 10 % of light speed, guess we need to factor time into this 11 min of thrust makes the universe see the missile at 10% of light speed 23 min to get to 20% light speed... 30 min of thrust and we have a 25% light speed missile, and enormously huge ranges involved in getting to this speed however.
The issue here, is when traveling at such speeds, even big targets get much, much smaller, since both are moving, and, ostensibly, one is evading somehow, meaning the missile must correct. The higher the speed, the finer the adjustments must be, since they must be made from much farther away.
And even at very high speed, the missiles are still vulnerable to light speed weapons.
Also if your missile are going that fast, you simply have the issue of the missile being "one shot, one kill" kinetic energy weapons. The warhead will become simple plasma long before it has a chance to detonate on impact. Better to replace the warhead simply with something heavy.