It seems like you're onto not one, but two major categories of possible spells. The example in your OP would seem like the more powerful type, where you perform a long-term ritual that lets you choose where to target the spell effects each turn during the long ritual. That seems interesting, but maybe too complex to make it through all the balance-hassling. But a multi-turn spell that simply intensified its effects on a single target, e.g. a dragon or a city, would be great fun on account of both 'chain' special effects and all manner of strategic decisions.

Are you seeing this as a sort of 'midsize' overland spell in MoM, where your base casting time and mana cost determine when the counter starts, but then you pay 'maintenance' only for the X turns that the spell takes to complete its cycle?

Just how I see the channeling thing (setting aside the fact that channelers are called channelers for the Shrads thing).

But chainning spells sounds interesting by itself.

Not chaining as written, but many games like this allow you to cast spells one after the other. I don't really see the difference between chaining a fireball and a summon fire elemental spell together, and simply casting a fireball, then casting a summon fire elemental.

Well, the point is that using a channel spell as listed in the original post would be stronger than simply casting them in sequence one by one, because it locks you into the commitment for that spell for 8 turns.  Ideally, chain spells would generally be high end spells that have lot's of umph if you can finish the whole thing and get it to land in the proper place--- but aren't completely vacant for the 8 turns you are casting them.  So really what a channel spell is, is the caster powering up something really, really powerful.  The effects that occur between turn 1-7 are simply side effects spilling out that you can put good use to.  Sometimes, those effects might not even necessarily be constructive.  If you cast a mighty meteor swarm that takes 8 turns to manifest the end effect, meteors might slip out during the process, crashing in at random locations (possibly your own troops.)  Whether you want to take this risk to get the mighty end effect, of course, is up to the player.

And besides, in Master of Magic tactical combat, every spell was--- poof--- one turn, be it a mighty doom bolt or a piddly starfire. 

What also might be interesting is if you could research your own spell chains.  You would have a certain amount of "points" to attribute to the chain based on some variable.  You would start out by deciding the build up effects.  If they are loose cannon, random effects, you gain extra points to spend.  If they are always positive, they cost points.  The earlier the effect is in the spell chain, the more or less you gain points.  Once you've fleshed out all of your build up effects, you pick an end effect. 

So you could have a chaos channel spell that completely throws random, possibly damaging effects for 7 rounds but gives the end effect even greater power.  You could also simply create a channel spell that is predictable and helpful all the way up to the final effect, but it wouldn't be a very big finale.

i am all for it, especially making the designable spell chains idea.

Often it is of great use to have a number of often even low level spells be cast at the beginning of the battle and making this into effects of a single casting of a channelled spell would spare much grief.

 On a related note it would be of great use to be able to advise a caster to cast a number of spells without choosing them in battle as spell tactic selectable before the battle (turn 1 cast barkskin, turn 2 regeneration, turn 3 flaming weapons... would be best to be possible to designate concrete targets in an existing army beforehand)

the channeling in itself is a great idea and is usable in strategic and tactical modes. Be it for the water to magma spell in strategical with global warming as a side dish, or as a fireball of doom in tactical, with fire arrows seeking out the targets before the big bad one is cast.

Dude, did you even read my post?  I just said that I'm fine with mechanics of magic and spells being explained and consistent, I even prefer it.  You asked for a reason, and I gave you 2 of about a billion.   Do you really think the devs don't have the imagination to explain something like channeled spells?  It makes sense from a game balance and mechanism perspective, therefore making it make sense in relation to the setting and game cosmology is very, very easy.  You're concerns were answered higher in the thread before you even mentioned them.  I think you can understand if I get annoyed when someone keeps bringing up a subject in an attempt to discredit a useful idea when it's already been given an answer.  Your concerns are legitimate.  They have been answered.  Anything further is just making argument for argument sake. 

Well, after winter's reply to me, i stopped reading BOTH your posts!  Forget stone walls for the city, lets put up text walls. Anyway, i understand where you are coming from winter. It dosen't make a whole lot of sense. But then, its magic, why would it need to make sense?

Perhaps instead of having elementals spawn, there could be a side effect to large or powerful spells. When you cast the super fireball, there is a chance that it will rain down little fireballs along its path at random points. Makes you be careful about just where you aim it to keep from splattering your own cities on its way out. A few quirky side effects would make some of the spells more intresting. Of course, not every spells should have them, but for some it might be nice.

Naw, its a great reason. Whenever someone starts babbling about it being unrealistic that an elf can shoot arrows out of the air, i always get a huge laugh. Its an ELF!! Of course its unrealistic. Its a fantasy game, set it up however you want, change any rule you want, throw logic and sense out the window. As long as its fun, its all good.

But i really do get your point though. The game should at least be internally consistent.

Will I get executed for saying I want magic like in the last two Harry Potter movies?

I'm thinking, specifically, the fire magic lord moldywart was throwing around in the fifth, and the one the headless headmaster whipped out in that cave.

You were declaring that channeled spells couldn't make sense in a coherant magical setting.  I said they could, and gave numerous examples.  I then declared that the dev's, who are responsible for crafting the story, were competent enough to work it into the story.  It's that simple, dude.  I've said it about 4 times already, and you still keep arguing as though I'm stating something completely different.  Well, it's obvious now that you simply can't admit error.

You are using smoke screens and mirrors to consistently shift your argument to smaller and smaller declarations.  I've only once on this forum accused someone of arguing for arguments sake, but it looks like I've hit #2.