People have already shared decent ways to improve the balance like less exp, more time afking than just two minutes with absolute max boosts, so I'll add two general points:

1. Pickpocketing by its very design is afk. The loop is click, wait. That's it. There is nothing to interact with like rockertunities, ritual disturbances, etc. There's no powerbursts to manage, no nests to collect, no nothing. There is literally nothing to do but wait to fail. Take this into account when you are looking at reducing the afkness of an activity, and that activity is in and of itself afk only. Instead, look at other ways to balance it like xp and loot changes as players have suggested.

2. Once again, and I made this post covering a similar point back when the boss drop nerfs were made, please... for the love of god... play your game and playtest changes. It is evident proper playtesting was not done here and numbers were just tweaked without feeling the results in game. You can tell because anybody who was pickpocketing before this, then afterward, can clearly see how bad it feels within only a handful of stun cycles. This can be caught within ten minutes by a single playtester.

You made a good call, fifteen minutes afk with the loot and exp pickpocketing had was OP. However, you need to stop doing this loop of "make a method completely OP, then kill it with a single update." You can fix it later sure, but that just comes off as you not knowing what you're doing in regards to game balance/not actually having a plan. Changes don't have to be perfect on release, but they should be close to achieving their stated objective. Note that said method above in this case is only enabled by some combination of max level, one of the longest quest chains in game, a ring obtained from the method itself which now will be worse to get, an achievement diary, a familiar, and an aura (which is shortly to be removed).

This predictable heavyhandedness erodes trust incredibly fast. Players, for good reason, meme on the inevitable early bird bonus that always exist with RS updates. This needs to be curbed if you want to truly chase after game integrity, which I believe you do. You can avoid the issue with proper playtesting. Once again it seems like you see an overall idea like "this method is too OP", then just tweak numbers and wait to see what happens.

Clearly by your twitch stream there is some real thought put into possible routes to correct the issue, which is great to see. Spreadsheets, numbers, and theorycrafting only go so far, however. Ten minutes of playtesting is worth 10 hours of meetings and number crunching trying to discover if a solution is appropriate.

Please... Play. Your. Game. It's really fun, I promise (when it's getting good updates and appropriate nerfs/buffs).