Yep, Sizzle pretty much summed it up. Normally I'm all about configuration options, but with something like that it's so core as to be something that can't be tweaked without affecting... so much else. If you want extra knowledge in a game, there's a cheat for that, but then it flags your game as a cheat game (as it's destroyed the difficulty balance).
I'm also not a fan of making the per-system knowledge a variant thing, that's been discussed to a fair degree in the past. I feel like there enough factors that people have to crunch in their heads when deciding which planets to take, and adding on an extra complexity of the knowledge-per-planet doesn't seem like positive complexity to me. It also could create knowledge-starved or knowledge-over-rich map starts based on the random map seed, which is something that would wind up tying players hands in an unkind way, I think.
I've been thinking about the numbers some, and I think that having the knowledge-per-planet cap increased to 2500 would be what would make the most sense. Some of the starship lines (thinking here of Riot, mostly) might need to be a bit more expensive in knowledge with that change particularly, as I feel like already they're already kind of borderline, but all in all this might ease the pain of the knowledge raiding takeaway some, and give players more options, sooner, without the tedium of the knowledge raids.
If you figure a player before might have knowledge-raided at least 5 planets if they were hardcore into that (or really, more like 10+, but we'll say 5 to be conservative), that would have been 10,000 extra knowledge than a non-knowledge-raider would have had in the game. That's equivalent to 20 planets worth of this extra 500-per-planet knowledge.
The difficulty of the AI tends to creep up over time, and has taken some jumps with the recent border aggression stuff and so on, so this is something of a rebalance of the game, but I think it will be a positive one. It prevents people from feeling like they need to knowledge raid in order to be able to play with much of the stuff (which, looking at the numbers, there is 300k+ worth of stuff you could spend knowledge on in a given game, so even with an extra 10k in a single game that's not game-breakingly too much). And that then frees us up to make the AI even more devious, which we certainly have several things on the slate for (the entourage behavior, etc).