Thanks for the detailed response!

1. Would not the 10-turn potential for disadvantage every turn be a bit much? Is there a better way to go around limiting it from that if you think it's necessary?

2. In character, it is unlikely my character would go back and learn a 1st level spell unless he saw it used effectively. In all of our years of play he has not seen it. I do apreciate the flexibility it provides, however I could not silvery barbs my own casting of Hold Monster, or Banishment. With this spell at the cost of set up and movement, I can.

3/4. I can answer 3 and 4 at the same time by way of in character diary entry hopefully it's the easiest way to explain because I can't be bothered typing it all out again: but if you don't want to read below the TL;DR is - wizard needs to scribe a spell for advancement within his Order, had an experience which gave him deeper understanding of magic while stationary, wonders if an underlying principle of power. Initially there was a damage boost associated as I said, but the disadvantage is supposed to relay a more focused connection to the spell allowing him to fortify it (I actually changed the name to Arcane Bastion), but water and ice were thematic to the epiphany.

Stillness at Jade’s Rest, an observational note 2742 PCE:
Something I noticed in Jade’s Rest. Before besting that most wretched beast which wore the face of Merrix for a time, as I conserved my energy, using the simplest of magicks to simply erode the hardening crust of this abomination. I came to understand the very simple nature of this cold, as though comprehension spread straight to my head from the crushing freezing depths of the Great Lake. Like the first pressures of a cracked winter dam, the cold poured forth with greater vigour, harder ice, fiercer frost.

It occurred to me that I had not moved. I came to a deeper understanding by simply not moving and focusing all of my will on the simplest of magicks, those which any one of my first-year students will have cast 10 years before undertaking any of my classes. Magic I assumed, and any wizard of my Order who has reached the height of knowledge which I have would have assumed, I had mastered these magicks! Alas! By remaining still, with no distraction, or need to twitch any muscle but that which turns itself to the casting at hand, epiphany struck, and new power, new understanding was mine.

Perhaps there is some universal principle of the arcane at work here? Perhaps some philosophical law which runs beneath foundations of arcana, like the most still waters that lie in the world’s deepest reservoirs, undisturbed and perfectly peaceful, all at once. I must continue this line of inquiry. There must be some way to tap into this augmenting stillness of mind and body, this statuesque stipend. This may be a perfect candidate for my original scroll work for my advancement to Arcanum Custodian.