The first buff was done because Advent didn't have an antimedium ship. What was wierd was Advent could easily be light firgate rushed and there was nothing you as an Advent could do about it. Your best option to fight a light frigate rush was disciples, and then your opponent would just bring in his lrms/assailants and maul you.
The first buff was desperately needed. It was really wierd when Illums did capital ships damage. The increase in damage was to offset the loss in damage multipliers. They overdid it though and nerfed it in 1.1.
Personally, I liked Illums when they did 33% damage from each beam instead of now where it's 20% for the sides and 60% for the front.
Of course, you must know, the Illum HAD to be buffed. LRM rushing and Assailant rushes absolutely crushed any advent player. There just wasn't much you could do. One guy called [Magog]Kruelgor proposed using disciples to counter LRMS........claimed you could outnumber then heavily. That's how outlandish and frustrating it was for Advent on rush maps. Now, Kruelgor was an extreme. I lived off of HC's back in those days. The destra and OP repulse in general saved Advent.
I dunno. Advent was really hard to figure out back then cause so few people played them and bothered to try. Newbs cried that they sucked, and the devs saw people weren't playing as them (myself not included, I loved the capital ships damage on the Illum personally). So, the Illum got buffed, but then it was OVERKILL. Carriers used to be 7-8 ship slots and supported one squad of fighters/bombers. Flak wasn't as strong then, so fighters did the job efficiently enough, but the devs were logical and saw the Illum needed a bit of a nerf.
Personally, I say the only race screwed by the Illum is Vasari. When you're best option as Vasari to counter a type of ship spam is to make flak (not scouts, too weak, not assailants=illum food, HC's too expensive early, LF's? LOL, fighters= flak food), the game has a problem. Not a complete break "Game is broken" type of problem, but something that desperately needs to be addressed.