God damn. I only got caught up to this and still haven't gotten caught up with Miharu. Before I say anything though, I must be clear on one thing; despite whatever will be done (or not), the end result must be simple, robust and easy to understand. I cannot stress this any more for one reason, and one reason only; new players. If it's not easy to understand and work with within a reasonable degree, new players will feel overwhelmed. Not only that, but some potential players have been discouraged from coming here by just looking at SARP. Keep that in mind as you go over my suggestions, please.
The current system is workable, but has holes here and there like how Star Wars Episode III had plot holes. We can stand on it, yes, but in the long term, not a good idea. As Uso pointed out about the manipulation of the shield threshold and mitigation, a bit of dancing and the shields' performance is maximized. However, as nifty as it is, is detrimental simply because it is another layer of material that must be understood to fully comprehend what is happening in the battle. The same goes for current interdiction rules, as a prior debacle pointed out in an unpleasant manner.
But we're not here to talk about shields and interdiction. We can easily raise another thread for those two and argue/discuss there. Instead, we're here for just the SP of the ships. I must say that, yes, there is a disparity between large and small ships. This same disparity is reflected in smaller things such as Power Armor and Frames, where a rifle the size of a Truck does as much damage as a shoulder mounted gun on a PA. But once again, I must keep myself on topic.
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Just looking at the numbers by themselves, it can be clearly noted that there is a diminishing return, as stated earlier. For a very large increase in tonnage and volume, there is a meager increase in SP. This means that all current action favors smaller ships, which is not a completely bad thing. But once again, as stated earlier, this also means that the Dreadnaught mounted up on the fireplace is much less impressive looking. The proposed, suggested, system put forward by Exhack helps to assuage this, but has its own problems as well. Even he has pointed this out, and it's terms are completely debatable and not set in stone.
Moving on, I agree that the jump from one cruiser class to another is harsh, until the size of the ships in question are taken into account. The heavy cruiser is twice the size, and twice the SP of the standard. It seems reasonable in this regards. But, canon must be accounted for; it ran off the current DR system and would seem to be incomparable with the new one. I have to digress and say that is not the case. Though on paper, it would suggest that it is impossible for a Cruiser to take on a heavy cruiser, we must keep in mind this is a guideline for how things Generally turn out. This isn't a JRPG where numbers count like crazy. Instead, the whole entire point of this table and the damned numbers is to give us Perspective. This is a roleplay. We come here for the story, the characters, the David and Goliath moments. Implementing this system, revised or not, would stress the miracle of instances where the small triumph over the big. The Miharu vs. the Takumi is a prime example, and would make their victory all the more important, not just because the Miharu and her crew pulled off a miracle, but also because it stresses that these tables are meant to be guidelines.
As the values are now they suggest large ships are useless; the one and only reason why they are not so in roleplay is because of Us. GM's and Players. What we do in the stories we have counts a hell lot more than the chart, further emphasizing the guideline nature of this proposed revision. The charts should reflect how we, as players and GM's, envision our ships and how they perform, not so much the other way around.