1) There is no upper limit for trade routes. Intended or not, this boosts research quite a bit. My 8 extra routes give me about 60 beakers extra per turn, plus another 60 from the 8 extra routes the Reynes has opened to my cities (so 120 out of total 300+ beakers, year 301). Partly because of this, I did not feel any significant change in the research speed compared to the bugged system some time ago. I built only a single library in the capital, did not bother with any other science-related buildings.
2) Summoning a Red Drake and the type II Demon was a bit troublesome. First 3 castings summoned the Drake far away on the edges of the map (there were free land tiles next to the witch, no errors reported). I could not move it if it landed on the sea (because it was hovering, not embarked). The 4th casting was quite good, but still the beast was summoned a few tiles away from the witch. The demon was successfully summoned by the 1st cast, but again, it was summoned a few tiles away. Weirdly, the tile was the one occupied by the druid, who was also a summoner. I don't remember clearly anymore, but I think the 4th Drake also appeared near the druid.
3) The death rune and seeing eye glyph markings disappeared from the map after reloading the game. The mouse-over shows they are still there. Turn 300 so could easily be a memory issue. I've noticed already much earlier that the main map city graphics disappeared, but on reload they are back though.
4) Tile yield display after blight is inconsistent. Before the reload I noticed yield on Man AI tiles with regular improvements did not change at all after blight, but now after reload they display no yield at all. Still, I suspect they give food because the AI city actually grew.. I will blight all the rest of the farms to be sure.
5) I hope there are plans on diplo penalty for actively blighting someones territory. Feels like it should be similar to the response as settling too near or buying tiles too close to AI. I have not tried to cast blight from the thaumatureges keep or any temple, it seems it would be a more stealthy but quite random way to blight my neighbors lands.