As you say, from an investor point of view, it makes sense to downvote whoever extract, on the other hand who stakes "protects" your investment from dumping on market his rewards...
I gotta say if you want to do downvote cleanup, the only way would be to make a total anonymous account, power up a fair amount of hive without being tracked and start cleaning... Don't even bother open notifications, just downvote and go on, like in a bubble
Regarding the 2 pools, it's not a bad idea, the lite one could be good to onboard people as it would look "rainbow social" or make content aimed to attract web2 users without hassle of not being enough original or personal, but it would open room for any kind of stuff, Ai, copy paste, etc... Would that be bad? Point of views, if I read a new medicine discovered to cure my illness, I'd say the post is worth more than a 0,01$ even if it's a plagiarized article, because otherwise I wouldn't get to know it, so it provided value to me