Exciting changes in WoW 3.1

I'm not going to list them, but WoWInsider has pages and pages of announced changes for all classes coming in World of Warcraft patch 3.1. And I'm not talking about minor changes that change some bonus from 3.78% to 3.83% of something. But major changes with huge impacts on how classes work and what their role is in various environments. Of course I'm most excited about the priest changes, where for example the spirit buff will be made available to all priests, not just the discipline spec ones. Discipline priest will get a group shield, and will be able to cast Penance on themselves. Holy priests will enjoy improvements to various AoE healing spells. And as some commenters remarked, mana regeneration will be reworked for all classes, and a priest talent that previously gave you some mana back for overhealing will now shorten the casting time of slower spells after casting faster ones. That means a complete reevaluation of what stats are necessary for priests, and a big change to our spell rotation.

My warrior will also have some fundamental changes to how his class works, because switching stances will be made significantly easier, and stance penalties might be changed too. The Arms tree will get increased damage. And I don't have to shout at the priest any more when he casts Power Word: Shield on me, because in future that won't inhibit rage generation any more.

Other classes also get some big changes: Mages and warlocks gain abilities that provide mana replenishment to their group. Hunters don't need ammo any more. Death knights get their blood and frost trees buffed. Paladins all get blessing of kings as base ability. And the list goes on and on, including several points where big changes were announced, but not specified, e.g. improving holy priests viability in PvP.

A lot of good stuff, and it looks as if Blizzard is improving some underpowered classes like warlocks. Which causes less protests than nerfing the overpowered classes, but ultimately does the same thing for relative class balance. Nevertheless I find the timing a bit odd. Some classes, like paladins, have undergone massive changes with every patch since 3.0, often going up and down like a yoyo. Other classes have been rather neglected. Wouldn't it have been better if all those changes to all classes would have come with either patch 3.0.2 or with Wrath of the Lich King? Well, at least it appears as if patch 3.1 pretty much covers all classes, so we might achieve some stability to class roles and class balance until WoW 4.0.

I've heard cynics saying that those class changes in each patch are Blizzard's way of keeping us occupied when new content isn't forthcoming. But patch 3.1 of course will have new content in the form of at least one new raid dungeon, and who knows what else. So what is your opinion on the frequent changes to various classes? Is balancing just very, very hard to get right? Or is patch 3.1 just adding stuff that should have been in the game long ago?