What makes a talent optional?
Optional talents are generally seen as those that don't directly increase your DPS yet afford you an amount of utility which is worth the trade-off; or, perhaps there simply isn't anything better to take within that tier of the tree. Improved Healthstone and Improved Vampiric Embrace would fall into the realm of optional talents; however, this is not the only form of measurement used to dictate whether a talent is optional or not. Talents that hold a nominal amount of DPS gain are also considered to be optional, provided that there is either a talent with a higher DPS gain that a player can take or a talent with viable utility that can be traded off for it. In this respect, the talents Genesis and Improved Insect Swarm are often considered to be optional.
Using a standard raiding balance druid build, you're usually only going to be left with two free points at the end to spend in what are considered to be non-core talents. With these, you can choose to pick up things such as Brambles or Gale Winds or Typhoon, Genesis, Moonglow, Dreamstate or Intensity. Should you happen to want to spend more than two points into one of these talents, then you could also drop a point from a talent such as Improved Insect Swarm without suffering a significant DPS loss. For this reason, we consider these talents to be optional, wherein you trade a highly insignificant amount of DPS for additional utility which you feel would be useful.
In my opinion, this is how the game should work. There will be a DPS difference between a balance druid who spends all of his points into talents which will directly increase his damage versus one who chooses to invest in a few of the optional utility. I would call this difference ego DPS; the gap isn't large enough for it to generally cause a pass/fail rate against any encounter, but it serves to make the druid himself perform better on the charts. This may seem to be a fairly negative term that I am subscribing to, opting to take pure DPS talents, but that is simply not the case. I support what I'm coining as ego DPS; I write guides on how to best reach it, and I spend hours simulating every aspect of the spec in order to push the limit on what we are capable of doing; that is the purpose of theorycrafting, and I never want that to die. Ego DPS matters, perhaps not to the development team, but to the player base; for that reason we need to have the option to push our DPS to the highest possible limits.
How is the balance tree looking?
I seem to have perfect timing on these things. I was speaking with Graylo last night, lamenting over wanting to do this post yet how restrictive the NDA makes it, when out of nowhere I got the astounding news that the druid talents for Cataclysm had been released to the public. Either I'm psychic or someone at Blizzard is stalking me; personally, I'm leaning towards the former.
Anyway, what you think of the current state that the balance tree is in is frankly a matter of personal opinion. I am of the opinion that it isn't exactly as I thought it would be, and I am slightly disappointed by this. Allow me a moment to clarify. When Blizzard originally stated their design goals, I went off the assumption that we would end up seeing more talents such as what we see with Brambles or Gale Winds or the current Celestial Focus. Instead, the changes are quite bland. Let me show you why.
This is what is more than likely going to end up being the basic cookie-cutter spec for all raiding balance druids, without exception. Note, though, that the two points in Dreamstate will actually be in Euphoria; in the preview they are not linked (and shouldn't be linked), yet Wowhead mistakenly has them so. The first thing you might notice is how the build has four spare talent points; this is because there simply isn't any place you could possibly put these points that will increase your DPS in any way. In all honestly, I like that about the build. This is a good thing. This is how I would think things should be designed. Due to the way that the talents pan out, a balance druid can choose to take Gale Winds or Fungal Growth without actually sacrificing any DPS at all. I love that because, as we've seen with ICC raiding, sometimes the fight mechanics support the use of a specific utility option, yet it sucks to have to give up actual damage on other encounters just so you can be prepared for the gimmick of a completely different encounter.
What I don't like is that a vast majority of our "DPS" talents really aren't DPS talents at all. Out of the 71 talent points spent, 15 of them are completely situational DPS increases: Solar Beam, Celestial Focus, Nature's Reach, Nature's Focus, Natural Shapeshifter, Moonkin Form, Improved Moonkin Form and Typhoon. Of those that remain, 18 of them are only a marginal DPS increase or focus on mana regeneration: Genesis, Blessing of the Grove, Improved Moonfire, Brambles, Omen of Clarity, Euphoria and Wrath of Cenarius.
This means that 33 out of 71 talents would be classified as optional -- possibly only 31, since the increased Eclipse gain effect tacked on to Euphoria is probably classified as mandatory. Despite using Brambles and Gale Winds as a shining example of what I would have expected most talents to now look like, a talent tree should not be so bogged down with fairly insignificant talents.
This issue I have with these utility talents such as Fungal Growth is that they rely entirely upon Blizzard to create boss gimmicks that allow the talent to be useful. Typhoon is a great example for this. Really, throughout most of Wrath, Typhoon hasn't been all that useful in the PvE side of things. There have been a few encounters here and there where it could be nice to have, such as Faction Champions, and the spell was always another possible tool to use while on the move, but the spell really never fit anywhere. In ICC, though, we got encounters like Suarfang and The Lich King where the utility of Typhoon was so excessively useful that Typhoon became a mandatory talent. As much as I enjoy having Typhoon, it irks me beyond belief that I only have it because there are two encounters where it's useful, while it serves virtually no purpose in all of the others.