[LadyLightning]

Technically, with Charge Mind lasting 3 extra rounds, you
~don't~ actually need HSDW. You'd be doing the following:

Turn 1: Charge Mind
Turn 2: Invoke
Turn 3: Blink -> Cast your Invocation.


whereas with HSDW, you would do this:

Turn 1: Move -> HSDW
Turn 2: Charge Mind
Turn 3: Invoke -> Cast your Invocation

Either way, you've spent 3 turns for that spell. With HSDW,
sure you don't get the chance to be interrupted, but let's
face it, there isn't much chance for interruption anyway.

Without HSDW, however, you've shifted your movement to
the moment before you release your Invocation, making it
a lot harder for them to run from it. Between Blink and the
range of Vydel, you can hit almost any square on the map.

At this point you've got the following skills set:
3 invocations
Charge Mind
Blink
Auto-Enchant
1 Enchant spell
Pure Power

That's 8 skill slots, three of which are optional, as some
people don't like to enchant, and some people prefer item
slots over +5 spell power.

Anyway, don't get me wrong -- I don't think that skill slots
should not be based on WIL. However, I ~do~ think that
they should also be based on SKI, or perhaps the higher
of either your SKI or WIL.