There are a few new systems appearing on the horizon that look like they will allow power control from any iso-compatible hotshoe, including those of mirrorless cameras like mft and Fuji X. But they're typically flash-and-trigger combination specific and are likely to be manual-flash-only on mirrorless. AFAIK, there are no full-function-TTL-capable radio triggers for micro four thirds, Fuji X, or Sony NEX at this time.
This one's actually a bit older. There are reports of this TTL trigger that works with Olympus's RC system to turn the light signals to RF; kind of like RadioPoppers. You should get TTL and HSS with this, and, presumably, remote power control, but reports are few and far between, and you'd still need a mft RC master unit of some kind.
Although initially the Cactus V6 triggers were not compatible with micro four-thirds, they've since updated them to work with a selection of micro four-thirds TTL flashes. The following flashes are now compatible with the V6's remote power control feature:
- Olympus FL-36R/Panasonic FL360
- Olympux FL-50R/Panasonic FL500
- Metz 44AF-1
- Metz 52AF-1
- Metz 58AF-2
Not the absence of the FL-600R/FL360L and FL580L from the list.
The V6 triggering system, however, like the Godox system below, is not a TTL/HSS-capable system, but a manual system that can manipulate the power control signals (for Canon/Nikon/Pentax gear, this means the quench pin signal, for micro four-thirds, it means a digital code for quench--which is apparently not uniform across all models). You can get HSS-like behavior if you stack it on top of an HSS-capable trigger (i.e., it can echo the pulses when sent by a unit that "speaks" the camera's hotshoe protocol), but this is typically only useful for Canikon users that already own HSS-capable PocketWizard/Yongnuo/Phottix/Pixel units.
The Godox FT-16s triggering system could work, since the transmitter unit works to adjust power in-hand, without talking to a hotshoe, so it's very likely to be mft compatible. But, obviously, it only works to control the Godox flashes.
Yongnuo TX units
And then there's Yongnuo. All three of their Canon triggering systems, with the appropriate flashes, work for manual power control on non-Canon hotshoes, but only the YN-560 system makes sense to an mft-only shooter who doesn't have legacy Canon flash gear.
The Yongnuo clone of the ST-E3-RT, the YN-E3-RT had a firmware update that allows it be used for manual power level adjustment on remote 600EX-RTs (and Yongnuo's YN-600EX-RT) from any ISO-compliant hotshoe. However, a 600EX-RT is expensive to use in a non-eTTL system as a manual slave, and having to hit the test button every time before a shot to send the power settings may not be your ideal.
The YN-622C-TX/YN-622C trigger combination can be used with an mft (or other mirrorless) camera to manually adjust the zoom, manual power level, and group on/off of any flash that's compatible with the YN-622C (as in, can be menu-commanded from a Canon camera), such as the 430EXII, or YN-568X. The new TX unit provides the interface that the Canon flash control menu does. Again, this might be overkill if you don't also shoot Canon and can take advantage of the eTTL/HSS features of the triggers on that system.
The YN-560-TX can manually control the power level, zoom, and group on/off on the YN-560III/YN-560IV manual flashes, but only these two models (the ones with the built in radio receiver). The YN-560IV can also be used as a master in the system, but only has three groups instead of six.