I have horrible lag on mine as well. I bought an Axon 7 thinking I'd use that for a bit until the new units arrive, hopefully along with a software update. I can tell you right now the Axon 7 is FASTER and snappier. I drive for Uber, and when a ride request comes in, I tap to accept it, it switch to the actual uber app, then I click on navigate to open maps. My Moto X pure did this faster than the Note 7, the Axon 7 did this faster than the Note 7...much much faster...in fact I constantly have horrible lag when doing this, and with maps app in general.
I also have a Tab S2 with a Snap Dragon 652 (mid range chip) which opens apps and runs fluid 3x better than the Note 7. Sometimes if I'm navigating, I'll get a phone call and my car stereo (connected via Bluetooth) will ring and show an icon to answer before my Note 7 can even display the answer/decline prompt.
There is something HORRIBLY wrong with this phone or software and I really hope it gets fixed. I'm not here to bash on the phone or Samsung. I'm here to say the lag is real, and there is an issue, obviously, with the phone. I had to return the Axon 7, because as other's have stated, the signal is very weak, I only got 1 bar on T-Mobile, however along with that, the GPS signal was horrible as well, so, while the Maps app loaded fast and was buttery smooth, the GPS signal itself was crap.