Lord David the Denied said:
You're exaggerating the issue. The Vorchan is the Centauri's fastest ship at speed 14". Most of the rest are around 10"-12". Most have no interceptors. If you think a single interceptor die on a handful of Centauri skirmish ships and 2 on the Maximus is "good enough to stop most damage" you're either seeing some bizarre dice rolling or you've given up before you've tried.
The Centauri fleet's weaknesses have been clearly laid out for you. Exploit them. Come back for advice if you have more problems, don't rant about how great they are while obscuring the issue with exaggeration.
Dave has a very good point here. It's quite easy to blame your own losses on another fleets seemingly apparent invincibility; but I can assure you as a centauri fanatic that they do have quite EXPLOITABLE weaknesses. Most notably is the very weak rear facing armament, meaning that a significant force of enemy vessels in the rear, is potentially devastating. I can tell you with first hand experience that a Sharoos class with three tigara escorts and a Tinashi are more than capable of ripping apart 3 primus with covran scouts and maximus escorting. However, and I'm sorry if this sounds nasty, but to make use of this weakness [unless using the hyperspace rules, which is how I got nailed] then you have to use something called tactics. Believe it or not, but ACTA is a very well balanced tactical game, if you are playing it right. If what you are after is a line up and shoot the crap out of each other game, go play warhammer 40 gay.
Now as most of the other guys seem to have already said, you either have an exceptionally good centauri player, who has an excellent grasp of fleet tactics and an indepth knowledge of his own fleets abilities, OR the rest of you aren't that good. Sorry if that sounds harsh guys but its the cold unadulterated truth. If you guys do have a sound grasp of fleet tactics, then I unreservedly apologise to you all for being that harsh, but sometimes you gotta be cruel to be kind.
If my opponent had lined his sharoos, tinashi and tigaras up against my fleet, he would have been playing to my strengths and not his own, and in turn, my knowledge of the centauri fleet, plus my own half decent grasp of fleet tactics would have ground them to dust. I had plenty of stealth beating tools around to counter the biggest problem with minbari. But you see, my opponent played to his strengths, outflanked me and got into my rear quarters, and did lots of damage. I don't moan about that loss, because it was a bloody good display of fleet tactics, and he deserved the win totally.
You can't blame the rules testers for the centauri rampage in your campaign dude, you and your commrades just need to get your heads together, work out where is killing you and play to your own strengths. There are plenty of additional SA's for you to use, such as run silent, all power to engines, come about and concentrate firepower, to enable your ships to further enhance their strengths and help negate their weaknesses.
Dude feel free to PM me if you wanna talk through some tactics, I use my centauri quite adeptly[apart from this one loss] and I know plenty enough on how to defeat a good centauri player . . . coz I am one.