i’ve noticed some of the wonkiness you’re talking about, especially having your character start walking or interacting with a nearby NPC when dragging items between stash/forge and inventory. it can be pretty annoying but it happens rarely enough that i don’t mind it too much.
regarding an easy way to buy/sell at vendors, you just need to hold shift and right click. this behavior is stated in a note at the bottom of the trade screen, but it can be easy to miss. i think it would be better default behavior to have this function tied to right click alone and the current right click behavior (equip item) should be on shift-right click.
(edit: it’s also worth noting that picking up and selling items to the vendor is a complete waste of time in this game. only bother selling uniques and arena keys if you don’t plan on using them. otherwise the vast majority of your gold will come from just walking over the copious piles that drop)
i also agree with the behavior of the waypoints… especially since the map takes up the entire screen… there have been many situations where i accidentally activated a waypoint while kiting a group of enemies and died (or came very close). i don’t think they should be activated by dragging your mouse over them while holding click. and there are definitely a few that are particularly annoying to click directly on in the recent patch (the ruined era lake with the void worm comes to mind… i had to click it in just the right spot when i reached it on a new character last night). i don’t recall having this much difficulty with them in the past, so hopefully it’s just a minor bug.
i’m not sure what you mean about picking up items feeling like a chore though… ever since we had area pickup added for shards, i’ve hardly noticed having to pick things up. that may be because i tend to scan things on the ground for interesting affixes and pick up very few items. the loot filter function has really improved this aspect as now my screen isn’t as littered. i’d highly suggest checking out the loot filter and heavy’s awesome pre-made loot filters and filter guide if you haven’t.