Dota will release tomorrow their all-new major patch 7.00. This features a LOT of core gameplay changes, including new mechanics, a new hero, sadly no new items but tweaks to all heroes (no exceptions) and some other stuff.
The official page is here: http://www.dota2.com/700
Some stuff of this might still change till tomorrow.
A small summarization of the biggest changes. First, the map will get (again) a complete make-over. The map will now be divided on each side in two jungles instead of one, a bigger one and a smaller one. Both sides will have more creeps, including a second ancient creep camp. Bounty runes will also now spawn only in the jungle, not in the river anymore. Neutral camps will now respawn after two minutes instead of one. Happy stacking then, if you mess up you mess up good.
Roshan will now be located on the other side of the map (left side instead of right). I think he was there already in the earlier phases of the game but I don't remember.
Heroes cannot gain stats anymore from level ups. That is, the "stat gain bonus" that you can use instead of leveling up an ability. You still get the normal bonus depending on your hero. Instead you gain now talents at certain thresholds. These are at 10, 15, 20 and 25, so you can have 4 talents. At each point you can select between two different talents, for example you can select between a +10 stat bonus or a cooldown reduction for all your skills. The most powerful talents are of course reserved for level 25 and these are most of the time fitted for their hero. Wraith King does not need any Mana for his ultimate ressurraction anymore or a bigger boost on his vampiric aura.
Additionally to this some heroes get now scepter upgrades. One is really cringeworthy and that one is Slark. Already one of the most hated, most annoying heroes int he game he can now be even a bigger pest with a scepter. He can now apply his ultimate on allies around him. Also halves the cooldown of his ulti.
You can check all the talents and tweaks to heroes and items here: http://www.dota2.com/700/gameplay/
Illusions will now give gold and xp depending on the level of the hero. Phantomlancer and Chaos Knight can ow be lucrative farming ictims if they are not careful enough with their illusions.
They also add a new backpack that allows you to carry three additional items that don't work there but can be swapped out at any time (however, with a small cooldown until the item works). Great possibilities there in the pro scene. Also nice for supports that can carry there wards in there until they need them.
The new hero is no other than the Monkey King. His abilities seem a little off. He can jump on trees, I don't know if he is invulnerable or invisible there but at least he can easily cross the map and escape from enemies that way. He also can disguise himselfs as trees, runes and other stuff on the map, to confuse his enemies. This makes it really hard to get a grip on him I guess. Even more annoying than slark?
His ulti is rather underwhelming, it is Rikis Ulti all over again, basically he creates an areay where he attacks all enemies at once but in his case with illusions instead of backstabs.
Also, the players for some reason don't like this patch at all. The rage is very real in the official forum, it is so toxic, you need to take a gas mask in there.
I'm actually a little excited. And a little scared because the most annoying heroes int he game just got a lot more annoying. But hey, that's Dota ina nutshell, you will always find that one game where you get curbstomped by a powerful hero that is hard to counter because you and your team picked the wrong items and heroes and realize too late what you actually need.