Shout and Preparation Mods

I was just wondering the other day why there are no mods that utilise shouts or preparations. Does anyone here have any good ideas as to why they were not made whereas others such as stance and enchantments made it in?

Mostly i thought of this because i get fed up of keep having to put my preps on my ranger and thought why the hell isn't there a "preps last 20% longer" mod like there is for enchants. But this applies to Wars and Paras just as much with their shouts.

A few ideas:

-'There is something like this for x and y, therefore there must be something for z' is not a satisfactory argument. z is not x or y, so the comparison doesn't mean much.
-Balance. Perhaps they wanted to ensure shouts and preps are kept to their intended length. Remember that they aren't removable, whereas both enchantments and stances are.
-Avoiding a lot of unnecessary shield mods. Remember that Proph only had inherent mods for shields so trying to get a good combo would have been much tougher. All professions had access to enchantments or stances whereas not all of them had shouts or preps.

Aye they are some valid points. But with your mention of unnecessary mods why include the conditional mods that have "when hexed" in there, surely that is not necessary.

I'm just wondering is all, please continue with more thoughts/reasons.

Also would they ever consider making them available, it would give rangers a semi buff that everyone seems to think they need. And Paras could definitely be helped with a shouts last 20% longer mod(and aye i know there are a few skills to extend shouts as it is, even though one is in a completely useless place, i'm looking at you VwS).

Aside from the fact that all 'while <negative effect>' bonuses are completely useless, perhaps they just wanted to give players the choice of bigger bonuses at the cost of having to bear the effect and not being able to control it themselves. Meh.

Then consider whether it would be better to just extend the length of the base durations rather than creating the mod. Adding a mod would mean you'd miss out on a +5 AL/+30 health mod, which may or may not be of worthwhile consideration. A 20% extension of preps would be a convenience tool for rangers, not really a viability modifications. Both professions have different and more significant problems.

That's why I don't use preparations on ranger or chants on a paragon, who want's to use skills with over 1 sec "cast time" on a ranger or anything thing but instant activation stuff on a para?