What are all the item changes you can see in second and following playthroughs in DS2? And which of them are present in the old "Dark Souls 2" game and which are at "Dark Souls 2 Scolar of the First Sin"?
Wiki lists a lot of changes, but also it says "Many merchants will add new items to their inventories" without specifying the merchants and items.
Another thing: the mentioned wikidot page seems to confuse DS2 and DS2sotfs, for example it says that the "Gower's Ring of Protection" is a new loot at ng+, but the page of Gower's Ring of Protection ring itself says that this is the case only for DS2, not DS2sotfs.
Also, is it correct, that at DS2sotfs you can get new loot only from bosses and there is no point to repeat thorough exploration of the areas?
Best Answer
There are a few items that change throughout the world besides boss drops and a few boss souls, but not that many.
Gower's ring of protection is actually one of those examples in vanilla DS2 (not SotFS). It can be found in shaded woods only in NG+ or after using an ascetic at the appropriate bonfire. Oftentimes, the loot will be changed for some (big) consumable souls (which is kind of a bummer).
I can recall 2 bosses that drop different souls on NG and NG+ cycles: The Rotten and the Duke's Dear Freja. Others will drop an extra item, like the Skeleton Lords. It's all summed up here. Fextralife wiki is messier and slower than wikidot, but it has more contributors so it tends to be more complete (although sometimes incorrect).
All in all, NG+ does feel repetitive, so you can either go blindly and turn every stone again with the occasional "sweet new item!" surprise, or consult the linked page and go straight to the novelties, skipping a large portion of the exploration.