Water-resistance. I don't take my phones near water, but there are cases where accidents or unpredictable events happen. For instance, while out in vacation in Da Nang, which is in Vietnam, while filming the Dragon Bridge show with my a6000, the camera along with every phone out there got drenched by spraying water, which was part of the show itself. The amount of water wasn't high, but the camera got wet, still. While it still works perfectly fine, having a water-resistant phone would really help in that situation, especially for the confidence factor. Of course, let's not forget those instances where your phone is on the table but you accidentally spill your drink. Or when you're in the middle of a call outdoors and it suddenly rains without warning.
I used to really need a removable battery, but with more phones being able to last a day on my usage pattern, along with quick-charging for those heavy days, it's not really a "must-have" anymore for my usage pattern. Of course, some people do need a removable battery, and as such, they may want that instead of water-resistance, and that is fine. No one uses their phone in exactly the same way as another, and that's really the thing to consider.
Of course, if a phone that has a removable battery that lasts a full-day on my usage pattern with the ability to swap it out and/or quick-charge it for those heavier days AND has IP68 water and dust resistance, that would be great for everyone here. But for that, you would need a rugged monster like the Rugtel Tank X10, and as such, I would pick water-resistance over a removable battery, personally.
If the LG V20 comes with an IP68 rating, that MIL-STD-810G rating from the V10 and a removable battery, some folks here would be happy.