Bottom Line: Touch-Trigger Preparations need a FAQ-clarification.
That being said, there are roughly three ways they can work out:
- Touch-Preparations are only good as traps - the mage makes them, drops them and hopes that someone picks them up/steps on them in the next few hours. Which would very severely limit their use, especially since that can be done in a lot of cases with timer-preparations.
- Touch-Preparations can be handed to teammates in a container, allowing them to trigger beneficial spells when they need them without the mage being present. This is what i would prefer to happen, since it gives them something you can't do via other magical means, including other preparations, and is something that can be seen in lots of magic systems (magic potions, prayer strips etc.).
- Touch-Preparations are save enough to handle that you can use them for offensive spells without notable hassle. I don't think that was the intention - handling out buffs to your teammates is one thing, giving them magical attacks another.
As i said, i'm most fond of the second idea.
But either way - even if touch-preparations get made worse, Alchemy will remain useful:
- It's easily possible to take half an hour to make some Preparations, take an hour to drive to the location of your run and heal a bit of stun damage in between.
- Preparations are best for sustained spells, not combat spells (ironic, because all sample preparations are combat spells). You don't have to do anything to sustain it, and they last long enough for any combat - so if you want offensive preparations, use Illusion- or Manipulation-spells!
- You can trigger a Preparation without being physically present - just astrally project and manifest, and you can trigger any command-preparation present.
- While its unclear, it seems like you need the more specialized Disenchanting-spell to counter an activated preparation, so less enemies will be able to do it.
- Last but not least, it only takes a simple action to trigger a command-preparation, so the drain is actually better than with reckless casting.