This week, Shimano filed patents for a Dura-Ace 12 speed group with wireless, electronic shifting. A patent filing generally suggests an upcoming product release for Shimano (although not always!) Such a group would compete head-to-head with SRAM's eTap AXS wireless groups (current Dura-Ace offers an electronic shifting Di2 option, but it's wired, not wireless.)
Such a group is ideal for competitive cyclocross and gravel riding. Since my preference is for the shape of Shimano's lever hoods and their hydraulic brakes, my next bike will likely have a Shimano, wireless, electronic shifting group upon release - here's why.
In addition to the on-bike performance, I also love the ease of cleaning electronic shifting bike. There are no mechanical cables to worry about contaminating with grit or moisture, and it's just easier to clean and shine up a Di2 or AXS bike to get it ready to race without cable stops and braze-ons in the way.
Electronic shifting, especially wireless, is not without downsides. You must, of course, charge the batteries that power the system periodically. SRAM says their wireless eTAP AXS setup can go about 60 hours of riding between charges, while Shimano's current, wired Di2 systems get even more - about 1500 miles on a charge. It's too early to tell, but we might expect a future wireless Shimano system to perform similarly to AXS - offering weeks between required charging.
A mechanical shifting system has a bunch of moving parts, but it isn't software. Introducing programming and software via electronic shifting adds complexity and is another possible failure point. The converse, of course, is that manufacturers can continue adding software updates and enhancements over the life of the product, while a mechanical group's features are "frozen" on the day you install it. On a software-based system, the rider can personalize the button orientation and functions as their needs or wants change.
There will always be a place for mechanical groups even as electronic shifting progresses to wireless. Backpacking and multi-day touring bikes, for example, are probably better suited to stay with mechanical shifting. You wouldn't want to carry a charger or diagnostic kit on tour, and mechanical shifting could be easier to fix in a remote location in case something goes wrong.
Although prices have come down, electronic groups remain more expensive than their mechanical counterparts. You might need new wheels, too - a Dura-Ace 12 speed upgrade is likely to require Shimano's new Microspline freehub body and would not work with the classic freehub design you probably already have. So you may need entirely new wheels; or a freehub swap if the wheels you own already have that option.
As someone who likes to tinker, the idea of tweaking and adjusting my drivetrain features from a computer or mobile phone is intriguing. You're already keeping your cell phone, headphones, etc. charged and plugged in, so what's one more device?
The cyclocross bike of the future has wireless shifting, hydraulic disc brakes, hidden, internal batteries - and I'm fine with that!