Alright lets break this down. Heavy Blaster flux to damage ratio is 36:25 (-36.1% efficiency). Pre-nerf Sentenia was a 12:11 (-8.7%) ratio, which is obvious miles better than anything else. Post nerf Sentenia is 7:5 (-33.
3%), which puts it basically on par with the Heavy Blaster, but the Cannon is still ~3% better. Current state Sentenia 5:4 (-22.2%), which is much better. The Cannon has slightly less DPS than the blaster, 200 more range, tracking, and no friendly fire. The Blaster has 8 less OP, and 5 times the alpha damage.
So calculating using 1000 armor, one Blaster hit will do 166.
6 damage to armor, while a Sentenia shot will do ~9.1 damage a hit for 90.9 damage a burst, if they all hit roughly the same spot, not accounting for armor loss during the burst. This makes the Blaster 58.8% better than the Sentenia against heavily armored targets, at least initially, and it only gets worse the more armor is involved.
So do you think the Cannon should be not be changed from its current form? Also, im curious as to what you think of the SKS cannons from P9 Megas. Do you think those are overpowered?
Also, what you said about using a Sentenia in a heavy slot is something I was avoiding bringing up because I couldn't think of a good way to word it, but it generally feels like the only ships that could handle the cost of the post nerf Sentenia were ships that had more large than medium slots, and I would rather use those large slots when I can, Templar weapons not withstanding. You seem to really really value the tracking, much more than I do, so there's not for me to say about it.
I will say the Sentenia seems more adept at killing smaller ships than larger ones, because of its qualities. That might be kind of a stretch, but it is highly effective vs fighters, and not great against armor. Your Hyperion example seems to be somewhat of an isolated case to me, and I have to say I don't really have issues with aiming at fighters, and if you're having a hard time or not wanting to spare the focus, just let the AI do it. Its probably better 90% of the time anyway. The range is something I can't contest. Because long range energy weapons are so rare, that 200 su is probably worth far more than it should be. But as I said, I think its good the way it is, but I think 18 -> 16 OP might be fine too. Would take some testing to see if it was too good, but I think it would work.
I don't think the nerf to the Crusader's system is good. The 1-second cooldown makes it extremely powerful, yes, but I think it really needs to be that powerful. The Crusader can't flee, dodge, or stay at long range, so its durability is all it has going for its survival. The extraoridinary staying power it has is its primary attribute and I think it's perfect the way it is right now. (But I'll withhold any more complaining until I actually get to play with the change.)
I do like the rest of the changes though.
You can make the Crusader changes yourself easily now if you like (not the shield changes though). I can tell you how if you like.