6.59b had no notable changes except for the memory glitch debugging.
v6.59 Update Commentary: (Here's the link for the changelog)
Notable changes affecting gameplay:
1) Ironwood branch cost reduction: Ironwood branch cost decreased from 57 gold to 53 gold. Definitely a plus. Often, I've found myself just one gold short to buy the branch. While this may not seem like much, the branches have one of the best resell values in the game and can be a life-saving item sometimes because of the +19 hp (1 str)
2) New mode -er: IceFrog added an Experimental Rune mode on this update. Here's what the changelog says --
"Experimental Runes: This temporary mode changes the rune system to a more experimental one. I will be changing how -er works from version to version to try out different ideas. I don't plan on any one version of the new runes to replace the current system directly, so do not panic Instead, it will be used as something to create discussion, spark ideas, find flaws and playtest different concepts over time. How -er works for this version: Runes spawn simultaneously on both sides at 3 minute intervals (instead of 2). Again I have no plans to make this permanant."
Interesting, but if he ever does decide to make the runes spawn every 3 minutes instead of 2, it'll completely change laning strategies of mid-lane heroes like Magnus, PotM, Puck, etc. who solely depend on rune racing to establish lane dominance. Still, he said that he wouldn't implement it on the main version so no need to worry.
3) Furion's Wrath of Nature mana cost decreased from 200/380/610 to 150/175/200: Wow. Real wow. This is such a huge buff, that we might even get to see Furion being commonly played in pub games. No need to worry about spamming this skill anymore mid-game, where it's needed most. Definitely a nice buff. :)
4) Windrunner's Powershot cooldown from 12 to 9 seconds: Nice buff, we'll get to see Windrunner again. 9 seconds is pretty imba for teamplay or killing fleeing heroes and improves spammability quite a bit.
5) Spectre's Spectral dagger no longer gives vision: I guess IceFrog has seen too much of Spectre in competitive play. No vision is bad. Real bad. It was bad enough already after he nerfed Reality by making it end Haunt on other heroes if it was casted. Spectre is soon going to descend from the Throne of Carries in Leagues.
6) Ursa's Fury Swipes buffed from 3 to 5 seconds: This buff helps Ursa get kills in his early game stages. I've seen heroes get away with 50 hp left because Fury Swipes ended. This one buffed Ursa's early game to a certain extent (not to mention, last hitting ability on creeps)
Most notable buff this time was the Furion buff. By far.
Next post... still thinking. Maybe a while before I post the next one.