Sounds like a huge buff to arcane and divine casters.
Do you give anything to other sources, to counterbalance it?

I think many 4E people have this "all classes need the same set of resources and similar numbers, power, and utility of powers" on the brain. They equate perfect equity with balance. It really is a very excellent marketing ploy by WotC to get people to think in one and only one balance mindset. If you give something to one class, you MUST give something to everyone else. It's a marketing masterstroke which brainwashes the DND gaming community into one set idea of what is fun and what is not fun. 4E is fun because it is balanced. 3E is bad/not fun because it is not balanced.
In earlier editions, the Wizard's AC sucked and his hit points sucked, so he actually was forced to either stay out of combat as much as possible, or he spent resources on defensive spells just to stay alive, or both. That left fewer spells leftover for amazing effects, so those other spells could be fairly amazing. Those spells were resources which could not be cast every encounter, so they could be more amazing.
Now that the Wizard's AC is fairly close to everyone else's and his hit points are not that far behind everyone else's, there is this idea that all of his spells need to be on par with everyone else's. Why? Because of a vanilla concept of PC capabilities. Balance is achieved by nerfing spells so that many of them have the limited duration of a single sword swing. Err, what???
So with regard to these house rules, if a player creates these types of spell scrolls, first off he is using up GP resources to do so. Secondly, he is helping the party when he uses them.
And finally, I think magic is so mundane in 4E that I have no problem making it more fantastic again. Allow the spell casters to shine as SPELL CASTERS a bit more and use other spells in combat. The spell power is the same as before and they use up monetary resources to do so.
Spell availability and duration has been throw away. As an example the Invisibility nerf flow of DND:
1E Invisibility lasts forever or until the target attacks
2E Invisibility lasts 24 hours or until the target attacks
3E Invisibility lasts 10 minutes / level or until the target attacks
3.5 Invisibility lasts 1 minute / level or until the target attacks
4E Invisibility lasts until the caster no longer spends standard actions on it or until the target attacks
It's absolutely amazing that WotC convinced millions of DND players that most spells should be one or two rounds, some spells could last the 10 or so rounds of an encounter, and that a few could go as fricking high as 5 minutes. All in the name of the one true god, Balance.
It boggles the mind how altered the DND gaming communities idea of what is reasonable has changed. This is not a dig at 4E. This is an observation how the thinking of millions of people has been changed within a year via marketing such that they cannot even conceive that their thought processes from a little over a year ago could still be valid.
The first thought when a house rule gives something to a class or set of classes: "Do you give anything to other sources, to counterbalance it?"
Instead of: "So do your players have fun with this?"
Balance is achieved by nerfing spells so that many of them have the limited duration of a single sword swing. Err, what???
Spells that can end a combat without reducing a monsters HP to zero pretty much don't exist anymore.
The Sleeping Beauty Spell or Fatiguing Sleep
or Welcome to the embrace of Deaths little sister.
This spell actually fatigues the target as a part of the magic and causes the loss of an appropriate number of hit points as part of its effect also the target is slowed with ongoing hit point loss save ends. If you reduce the targets hit points to zero he is in either a perpetual coma that requires a fairly serious ritual to remove (alah a certain faerie tale princess) or in a very groggy hard to wake from sleep (often called unconsciousness) <= Casters choice of which as the two are subtle variation of the same magic.
Different damage types exist the most common : poison and psychic and cold... often visualized as a gas or wave of scintiallateing sound or light or even a wave of cold that creeps from the inside out stilling ones energy.
In some forms of this hit point loss induced by this effect may be paid on a two for one basis with Temporary Hit Points.( ie 1 thp loss reduces the hp loss by 2).
The primal version of this is said to bypasses ones passion (temporary hit points) entirely.
Some forms of sleep magic actually allow the victim to use a healing surge if it fails to reduce there hit points to zero.
A very controlled version of it was said to be used to bring Battleragers to there senses and only causes loss of temporary hitpoints only in a relatively large area of effect.
Things, huge, violent, gameshattering things, had to happen to spellcasting in dnd. Thankfully, they did. Some further adjustment would be welcome, but it shouldn't be made blindly.
I like everyone at the table having fun. I like everyone having moments where they contribute to the fight.
When my spell caster cannot do anything but throw damage, there's a problem. IMO.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.