If reinvesting sci eats 10-20% of the books, or something in that range... you really just want to direct your own sci investment to rebalancing over time. 'Tis primarily intended to allow an NW drop after a deep chain, to take yourself out of range. It costs, and fairly hard, but gives you an "out" for the "NW bloat". Now... turns out, for housing sci serious NW bloat won't set in till at about 10,000 bpa (yup, read that number again), so I don't think it is actually a problem often enough to care about. But it is in theory a situation where it'd be helpful. (And it'd help a T/M that gained military sci on a learn... although how that'd happen is a bit beyond me.)
Halfer - I like the elite as is. It is stronger than it looks, though it isn't broken the way it was before it ate the NW nerf in the final changes. I've always thought dwarf as a better fit for a 6/5, 6/6, or 7/6 choice (6/6 is hard cause NW hurts the offensive use of it) - halfer feels good to me. 6/6 at 6 NW is too strong with halfer's other buffs. Although... the 6/6@6 on offense is actually worse than the o-spec 5/0@4. But the drop of .25 NW, and the fact that you eat a lot less NW bloat from running a partially dynamic defense... ok, not a bad change. I ran the numbers and it doesn't make a big difference in balance, and I'd consider it a fine tuneup *if* halfer were coming up a bit short on power. I'll tell you if I think so after the age - so far it's power looks good though, so I'd recommend against this buff (in isolation).
Other stuff... ya, tuneups of the interface are good. Separate from balance, IMO 'tis a different thread. I will highlight: "swap" with kingdom member - this can already happen, but is abnormally pricey (takes 3 trades?) - a way to do it at 1 trade cost would be cool. Needs a "cooldown" or cost of some sort so it isn't a tactical option though. Otherwise 'tis just a costly x-logging feature, which is bad. (Have we considered that problem for normal trades enough?)