I think we all agree a "pickpocket with discipline" stunt would work, skinned as magic, just as some forms of "zero stress" battle magic are skinned that way (eg, substitute discipline for athletics to dodge to simulate fast deflection spells)
If you don't want to spend precious refresh on it, thaumaturgy can clearly do the trick, but it lacks a lot of the advantages of a rote. So a wizard with pickpocketing on his mind would only want a rote if the idea is to do it really fast, under high stress situations (such as combat).
The main concern isn't that evocation can't be subtle, it is that all it can do is block, maneuver, attack and sometimes move.
Thaum lets you "solve impossible problems", a much broaders scope, and is the source of most skill replacement stunts.
Mechanically though, taking something away from somebody is a maneuver.
Doing a maneuver without being noticed would require some kind of veil (block vs awareness) or maneuver (a distraction type aspect you would then invoke with the free tag to not notice the pickpocket).
So either you want two rotes, and two actions, or you need a rote that combines say, a veil and a maneuver with more shifts. Given that you can probably combine an attack and a maneuver (Fuego as often portrayed in the books is something I would skin as a fire attack with 3 shifts dedicated to a "knocked back" type spirit maneuver which is then immediately invoked to toss the guy into another zone) a high enough shift rote (6 shifts maybe for two maneuvers or a maneuver+level 3 veil?) might get it done in one action.
What do people think about combining effects via more shifts, rather than one massive effect? Is that one of those things discussed to death or is there a consensus on that (I can see action economy balance issues, unless you also allow a high result non-magic maneuver to attempt two maneuvers at once...although again, why wouldn't you be able to do a supernatural strength punch that sacrificed some shifts of damage to put a maneuver on somebody....similar to the fuego suggestion above)?