Our vision for the game is an ambitious one where the power level between different builds remains low so that any build employing synergistic items, skills, skill specialization tree nodes, and mastery nodes can be successful and considered viable.
I have previously written about World of Warcraft, and the distinction between perceived differences of power and actual differences of power. World of Warcraft has 36 specializations - each having access to 16 equipment slots (two-handed weapons occupy two of these) and 18 talents. In spite of this, Blizzard has typically done a remarkable job in ensuring that any differences in the effectiveness of the various specializations are minimal.
Our skill specialization trees are designed to give us many different knobs to turn in pursuit of balance. Because every skill will have a specialization tree - and each of them will be unique - buffs to one weak skill won’t cause a competitive skill to become unreasonably powerful. This affords us a great deal of control over just how strong each ability becomes.
There will always be cookie-cutter builds to some extent - these could be ranged builds with crowd control such as the Warlock, or minion-focused builds which utilize meat shields to deal damage comparatively safely. These can be balanced in various ways - the Warlock might not have the raw damage of other masteries - while Necromancers may struggle to balance their minions’ damage, their minions’ survivability, and their own survivability.
Some ARPG players enjoy the core gameplay loop but not the theorycrafting, and others like creating guides which the community can follow. So long as there is not a large disparity between the flavour of the month and other builds, that’s not necessarily harmful. In fact, it is a sign of a healthy community where veterans of the game help new players learn how to build their characters defensively, how to defeat bosses, and so on.
None of this is intended to suggest that I think we’re infallible and our balance will be perfect from day one (or ever!). I’m just saying that the ability for players to build a character the way they want to and be competitive is important to the team - and we’ve kept it in mind when designing core systems such as the skill specialization trees.