I thought modifying RCC's with sleaze/attack was errata'd out?
A cheap deck and some hacking skills is not that huge of an investment and does give this option to riggers.
Sleaze is also used for staying undetected in the Matrix, which is important for infiltrating/scouting a location with Drones, the fact that it was left out in the first place was already bullshit,
and basicially made it impossible to get Drones in anywhere with a Spider. Requiring a Deck in addition to everything else a Rigger needs, just to do something you're already supposed to do, isn't really a good solution.
A good dongle isn't exactly cheaper then a Deck, but you don't run into Slave/Master issues that way.
Can a device be slaved to two different master devices?
Wouldn't break the either Master or Slave rule, and having multiple PANs was never an issue.
It could be one way around the "no Dongle for RCC" issue. Simply Slave your drones to both the RCC and a commlink+dongle/deck, enjoy being able to stealth.