Energy shield was recently upgraded by an improvement to mana burning. So even if you pay 30-40 points to increase the energy shield to build, you're better off investing your points in damage synergy rather than warmth since meditation will completely eliminate Warmth.
Level 1 Meditation grants 300% mana regen in comparison to 30 percent from warmth.
Insight, a level 12 meditation gives the possibility of 575% regen. It can go up to 700% by level 17. The warmth on level 20 is 258 percent which is not even near the level 1 equivalent of meditation.
Meditation acts as an AOE party buff that is available through a merc as early in the game as high level. Warmth is an active buff that offers synergies with fire-related skills that are wasteful at the end of the game (inferno fire, blaze, firewall).
Enchant can be used for a variety of reasons, however melee-based sorc builds were wiped out by this patch thanks to the huge nerf to the speed of bear attacks (on this note, why holy fire does full damage to weapons ranged but enchant can only deal only 1/3 damage)
Late game gear isn't a requirement for warmth, and the one build that could be used of this (Level 40 ES, with maximum Telekinesis) cannot be able to afford the points since not a single damage skill can be considered a viable option at the end of the game, with only 40-50 point (Frozen orb
With low mastery is the sole semi possible option that can be made with enough points to cold mastery for resistance of 150 (or less) ...
Are we thinking about improving the basic skill, or, at a minimum, consider adding synergies to abilities in other trees? At present the mana pots are just pop until you obtain a merc using Insight after which there is no issue with mana until the end of the game.