Update 26th June: moved all the "item changes" into their own category. Most changes to items are very similar. Kept the "miscellaneous" stuff on the first section. Added links to all items mentioned (for easier referencing), and added everything else I saw here and on reddit.
Let's put together a list with all the undocumented changes (aka not in the Patch Notes) for Patch 2.1.0 (PTR).
I've already added a few (from reddit), and I'm sure you guys will spot a few more.
First and foremost (as this will be repeated a lot below): lots, lots, lots of items have had changes to their "base affixes", some had "meh" affixes removed from always rolling (like Blackthorne's Life%/attackspeed/LoH), and quite a few were changed to roll 5 Primary Affixes (up from 4 maximum).
While this does make these items considerably more powerful, bear in mind the more difficult stages of Greater Rifts (lvls 40+) will probably require a lot more power than what end-game characters have right now.
Malthael XP is fixed. You get the xp from kill only after his death animation now (no double kill xp anymore).
Gold drops now show (the amount on the ground)
Your last sum of your gold within ~5 second time frame now shows in the lower right hand corner
Meteor Shower's tooltip updated. Now it displays "Unleash a volley of 7 small Meteors that each strike 228% weapon damage as Fire".
The goblin from the puzzle ring no longer glows.
QOL change: Holding down a button will now recast that spell when off cool-down.
The spell will not go off if you have another skill being 'permaclicked' when the cd ends (channeling spells or hold position+autoattack)
The spell will not go off if you are running around by keeping left button clicked at all time (You have to release it slightly before the cd wears off)
consequence from 1 you cannot have two cd spells kept clicked at the same time (only one of the two will go off & priority seems to be given to the one with shortest cd no matter which one you started channeling first)
Also clicking your main skills too fast (if you have high AS for example or if you are a SC born clicker) while having a cd skill channeled might prevent it from triggering. Most likely every click trigger an extra internal cd to the skill like 0.3 sec so if you click faster than that you will permablock said skill. (mechanics tested by Masterswipe)
Fixed a bug where crusaders wouldn't get nephalem glory buff from picking up an orb while using steed charge.
The gas from Ghom rift guardian doesn't hurt after you kill him.
Red Nephalem Globes are in Higher Rifts fill your completion bar.
Screen shake has been deleted or added to certain skills
Quivers can roll elemental % damage now (one of the 5 primaries). I got a quiver (one that doesn't have any special effects) that rolled 20% fire, and Kadala can reroll it to any element. could be a specific quiver that has been added to roll an elemental affix
Holy point shot now rolls with elemental damage (can roll all different ones, not just one specific like winters flurry/fire birds eye for wizards).
Northern highlands has been "nerfed" (no longer guarantee 2 goblin spawns and 1 cursed chest spawn - on live there's always 1 goblin in the downstairs area, and 1 in the upstairs area, and always a chest in either location, occasionally two).
Previously reduced damage from melee attacks by 25 - 30%, now reduces by 44 - 50%... and this change is retroactive, unlike the majority of other legendary changes. A Stormshield I have from Live is now up to 49% melee reduction.
The proc from Baleful Remnant (http://us.battle.net/d3/en/item/baleful-remnant) now always procs if enemies die near you, no matter who kills it (now procs on assists as well would be the best way to word it, I guess) - previously you had to be the one to land the killing blow (even the avatars from the weapon would not spawn more avatars before).
Sorry for Off-Topic..
But how long does it usually take for Blizzard to drop the real patch ?
No one can tell you, it varies greatly. If we had any indication, it'd be all over the site already.
An unqualified guess, considering what has been implemented (backwork for new legendaries, greater rifts, change of old legendaries, leaderboard, initial class changes) and what hasn't (seasons, new legendaries in the game and tested, legendary gems in the game and tested, further refining of class balancing) I'd say no less than a month, probably closer to two. They'll probably keep the current state of PTR around for a week or so, gauge how people are doing and let them get used to their new class synergies, then roll out a patch update with further refinements to classes, new legendaries, and legendary gems, and test them for a few weeks untill they make the final pass, and test that for a few weeks aswell to make sure everything is as it should be.
I noticed that pets from other party members are transparent now so it's easier to see what's going on if you're playing with another player with lots of pets. unless this change happened earlier and I just never noticed. >.>
I might be going crazy but I feel like the icons for Forgotten Soul and Reusable Parts has been changed.
Kadala now says positive things when you get a legendary or set item. I got "what a steal!"
There is a gold counter on the lower left quadrant of the screen. It seems to count a total amount of gold you collect while collecting gold. Disappears after 3 (?) seconds of no gold collected. This is nice if you have gold pickup/ gold find sets.
Also, labels for amounts of gold are once again present on gold piles. (Thank you!)
Pretty sure this is new... After about one second, Crusader's Steed Charge can be ended early by using a different ability - previously you had to wait the entire duration of Steed Charge to do anything.