Well, knowledge raiding is legitimate, but it's meant to be really, really hard and not something routinely done.
As far as there not being enough knowledge for unlocks, that's a completely different discussion, eh? The knowledge-per-planet could always be adjusted upwards as the game evolves and there is more content competing for the players' attention. However, at the moment I've been viewing this as "more opportunities for specialization" rather than "more opportunities to have everything at once."
But knowledge balance and ease of knowledge raiding really should be unrelated discussions -- it's only another sign that knowledge raiding had become too core of a thing that the discussions get blurred in that way, and makes me even gladder of the heavy knowledge raiding nerf.
The more I think about it, the more some sort of per-planet knowledge cap buff makes some good sense, with the recent additions of so much stuff people want to use. I would think maybe something small... 2250 instead of 2000, or something. 2500 at absolute most, but that seems like it may be close to overkill.