Welcome along - enjoy your new ride.
Problem areas back in 2012, were several QC issues, all of which the mothership has pretty well sorted out by now, albeit a tad slowly at times. Hence the suggestion by Andy that you get your local dealer to run up a print of precisely what work has been undertaken, both under warranty/goodwill & during service.
Several issues were exposed by early adopters, most/all of which will have been sorted on your bike by now, including: -
Switch gear - both left & right suffered failed encapsulation/water ingress, which wasn't funny if the kill switch acted up.
Coolant pump - some weeped excessively & created coolant splatter as witness on the pipes.
Suspension Units - Front & rear damper failures were not uncommon.
Gearbox - Always a pretty clunky affair, but some suffered extreme lash in the transmission, which often meant a replacement gear cluster; hopefully under warranty as these didn't come cheap. 2014 saw improvements.
Piston Ringlands - several reports of piston failures detailed on the forum. Very unpredictable, possibly pre-ignition.
Corrosion - several mentions of engines being replaced due to excessive corrosion.
Coil Sticks - some failures, often on either No1 or 6 that are more exposed.
Cooling - some riders have experienced the red warning rather more often than they would wish. Sometimes it was the techs failing to burp the system at a coolant change, sometimes a dirty rad (lower third), sometimes it was just the bike expressing it's dislike of conditions, say slow mountain pass rides with little airflow. Cooling is a tad marginal given the engine design, rad size & single fan, so keep the rad scrupulously clean & maybe use a fender extender.
Otherwise, apart from eating the odd tyre, I think it important to maintain a decent warranty for at least a couple more years if possible. Parts/labour costs can get eye-watering, unless you are very handy with the spanners.
Looking at your questions, the throttle is something you need to just accommodate. It's an FBW system that can be a tad difficult to ride around at first. However, do make sure the cables are adjusted correctly. As for mileage, that's no problem, subject to strict maintenance of the service regime. I always like to check this out, particularly on low mileage bikes, just in case the regimes have been shall we say abbreviated - unlikely if you have a BMW used bike warranty running, as the franchised dealers tend to pass any questionable bikes into the trade. BTW, make sure you understand oil level checking - it is easy to overfill if not done correctly.
Have fun & run a few searches around the forum if you still have any areas of concern.