Someone should explain, and maybe put it in the first post, about what this means for people on the fence. Otherwise it's just a big confusing wall of text.
Okay I am on my phone right now but I will give it a go:
- several of the rules has been altered ( not core rules like the goal of the game and the basic format of the map etc. They are the same) these changes include:
1-the length of the Day and Night cycles are shorter (4 minutes instead of 6). At night time many heroes will get a smaller line of sight while a minority get to maintain the same line of sight during the day light or have an even bigger line of sight. This means players have to spend even more time playing cautiously then before and it also buffs heroes that benefit from night time.
2- Roshan respawn time is a bit random now: Roshan is big neutral creature on the map that gives a lot of gold and exp to your team if kill it. It also drops an item that lets its carrier respawn with no penalty in the same location they were killed. It's pretty darn important.
Before, Roshan always respwaned after 10 minutes. NOW it will respawn at some point between 8 and 11 minutes after he was killed. This change really effects the pro games where they time the respawn time perfectly.
Overall, this change helps the losing team and gives them a better fighting chance.
3- the jungle changes: I don't play this role often but the jest of it is that the strategy to gain the maxmuim benefit from tge jungle for all heroes (by killing/manipulating the neutrals in the jungle) has been forced to be changed, for better or for worse. It can also indirectly benefit the enemy team via netural exp split.
-almost every hero got some significant balancing/nerf/buff. Some of those changes are HUGE and will change the way we build and play the hero. An (striaghtforward) example is the nerf to Batrider. He has a 100% pick or ban stat for like a year now in pro games. Now he got nerfed just enough that he will not be picked as often and will be less dominating in lane.
Summary: if you never played Dota 2 this patch won't really affect your first impression of the game.
Hope this is the answer you were looking for, or I might have misinterpreted your question.