The climb
Bands above the second no longer get easier as you climb them. This was the big one. Every band except the first had a single flat difficulty ramp inside it, so foes near a band's gate hadn't kept pace with a cultivator who'd been gathering relics and strength all the way up. At the fourth realm, 91% of fights at the top of the band ended in a single blow. They now hold or sharpen as you climb, the way the first realm always did.
Ordinary foes at the third realm and beyond carry teeth again. Crossing out of the early realms used to make the tower safer, the chance of meeting a foe with a stormclad guard, thorn-boned hide or venom in its strike dropped from 40% to 26%, and didn't recover until the sixth realm. It can no longer dip: no band is less dangerous than the ones before it. An over-curve build still ends fights fast, and still bleeds for it.
The deep tower stops flattening out. Pressure kept rising with depth but hit a ceiling at the seventh realm; it now climbs considerably further before it levels.
Your cultivation cannot outrun your realm. Base-camp upgrades now have a ceiling per realm. Comprehension earned at that ceiling isn't lost, it banks, and is yours to spend the moment you break through. The shop says "realm limit."
Things that were lying to you
The peddler's stall was advertising a fraction of what it sold. A pill that granted 12,510 strength at the fifth realm described itself as "+10". The reward was always correct; the label wasn't. It now says what you'll actually receive.
Sect life
Each order names its demeanor, Orthodox, Demonic or Neutral, beside your standing with it, so you needn't leave for the codex to know who you've been dealing with.
A promotion tells you what it bought you. Rising to Inner Disciple grants a permanent edge with your sect's element, but it was a silent passive behind a new title, so rank felt like it did nothing but pay a stipend. Every rank now names what it grants.
Quality of life
Goals pay. They named sixteen things worth doing and rewarded none of them. Per-climb goals now grant spirit stones; the long lifetime arcs grant comprehension. Both scale with depth.
Windows fullscreen is borderless, which should stop a second window appearing when you alt-tab, and a second launch now exits instead of opening its own.