This is extremely disappointing. I plan to post a YouTube on it later this week showing how the behavior on the my new MacBook Pro does not operate like my former MacBook Air, my current, yet older 15" MBP w/ Retina display or the Magic Trackpad. 3-finger drag works flawlessly on all those devices including the latest Mac OS X as it has on prior versions of OS X. Neither is this specific to a particular app as the inconsistency exists within the Apple apps, Microsoft Office and Adobe Lightroom.
And, no, do not expect it to be fixed by replacing your hardware. Due to this I (and the poor battery performance) I exchanged my 2016 MacBook Pro 13" with a new one. No difference. This problem is the same. It is not a problem with your machine, it is a fundamental flaw in the design (hardware, software or firmware or whatever) in the new MacBook Pro. So along with the extra dongles you will need to carry a Magic Trackpad or you will need to revert to guestures more akin to what you do on a Windows machine.
I do not have 10.12.3 installed but if the above post is true - that it does not eliminate the problem - then I strongly believe it is a flaw in the hardware design and was not sufficiently tested during engineering. When coupled with the apparent failure of Apple engineering to get the new batteries up to spec (and needing to resort to smaller, older battery design) I believe these new MacBook Pro models were a major fail on the part of Apple who felt the need to get to market and/or did not do adequate engineering. We may begin to hear excuses such as "It is a user problem." Or "We never said you could use 3-finger drag that way." Or whatever. I have been a long, diehard Apple fan. But I have just directed my organization to cease all purchases of Macs and to begin a pilot with Windows products. Sorry, but the "just works" that made us so loyal to Apple no longer works.