The most significant gameplay change that supersedes all, is that
Maelstrom as a resource is gone, and is being replaced by
Arma del Maelstrom. The core directives of the spec have shifted away from using
Araldo della Tempesta to enable
Assalto della Tempesta spam, and has instead moved to more intricate cooldown juggling. This is done via various cooldowns, all of which have their cooldown times reduced by Haste:
Due to these all having different cooldowns, the primary goal is to make sure to keep the lower cooldown options active despite lower upfront damage, and to use the longer ones to offset downtime. This doesn't stop downtime happening, however, and the primary mix up to this is
Arma del Maelstrom, which has a 20% chance to generate a stack on any melee hit up to a maximum of 10 stacks. Each stack reduces the cast time of either
Dardo Fulminante or
Catena di Fulmini for damage; which you are using depends on target count. At 5 stacks this makes a cast instant, allowing you to effectively bank 2 uses to fill when needed. Note, unlike older iterations, we
never hard cast these below 5 stacks when in melee, since they reset our swing timer.
The pre-patch will not grant access to our most important AoE passive component for
Tempeste Infurianti, and losing that cooldown reduction will slow AoE enough to hurt the flow, but it does become a very tight cycle come Shadowlands proper. We do, however, get
Catena di Fulmini casts feeding damage into
Schianto di Fulmini, so there is more of a flow to get used to on AoE that will prime you for Shadowlands release. We also have a strong amount of rotational synergy with our Legendaries, and not having access to those has a more visceral feel than just lower numbers. Some talents don't come into their own without access to the Legendaries' mechanical effects, so bear that in mind.
As mentioned above, in Shadowlands, there is a significantly higher cost to utilizing our self-healing tools. Instead of only 20
Maelstrom that can be generated instantly, it costs a full 5 stacks of
Arma del Maelstrom to use. While we can use this on
Catena di Guarigione to assist the group with the heal slightly more punchy than before due to the stacks increasing the healing done, using these tools impacts your DPS to a significantly higher degree than before. However, it does still trigger expenditure rewards such as
Tempesta di Grandine's effect. In many cases, it's going to be preferable to defer to
Totem del Flusso Vitale as a low impact quick heal due to it having no cost.