I don't disagree on certain of those points.
Blizzards problem with WoW is simply this, it's too big and they have moved from making themselves happy with their product, like with the original WoW, to making the 9 million people that play it happy.
Ima nerd out real quick here: Just compare the final bosses in "vanilla" WoW, Ragnaros, Nefarian and C'thun(not counting KT, he made a reappearance in Wrath). Anyway, Rag is a 50ft tall fire god, Nef is a black dragon that dwarfs Rag and all you ever see of C'Thun is his eyeball and maybe a portion of his stomach. Fast forward to BC, the "big bads" are a Naga(Lady Vashj), two insane Elves(Illidan and the other one who's name escapes me atm), and their boss, a demon trying to invade Azeroth. While it's handled relatively well, the baddies are all smaller scale physically and simpler encounter wise. Now, with WotLK, the "big bads" are a Lich, a potato with about 30 mouths and a disembodied brain, a renfaire and The Lich King(who for all intent and purpose is an overpowered necromancer with a bad attitude and delusions of grandeur). These are even smaller scale battles than BC. The "epic" is almost gone from the game.
With Starcraft, their trying to recreate the "lightning in a bottle" that the original had. The mistake that they seem to have made here is that people are going to get turned off by the idea of having to buy 3 games to complete the story and be able to play all 3 armies in multi. The whole Starcraft 2 and 3 separate releases reeks of Bobby Kotick milking a cash cow till it's beyond dry and tossing it in the bin. It's happened before and it'll happen again. When all of SC2 is out we'll probably get a release announcement for SC3 and discover that it's been in development for 5 years.