The Cabana Bar at the Dolphin doesn't have the greatest view, I guess, since it essentially looks over the lap pool before you get a view of the lake separating the sister hotels, but it's still a relaxing location and vibe. It's definitely one of the best places to relax with a drink on property.
The Victoria Falls Lounge at the Animal Kingdom Lodge is on a terrace that overlooks Boma, and the staircase to Boma and Jiko. It's a decent place to people watch, and it you get tired of that you can settle up and take your drink(s) out on the back patio to sit around the campfire and watch the animals on the savanna. The same can be said for the lounge at Sanaa in the Kidani house, although the view from that bar is blocked by a wall. Still, if you plan on taking your beverage with a safari chaser, the Sanaa Lounge is rarely ever crowded. It's much easier to get a drink there than at Victoria Falls to head out on the viewing deck.
Also at the Boardwalk, the outdoor seating at Big River is always a good call, weather permitting, of course. Lots of people walking by and an unobstructed view of the lake and Friendship boats make for a good, quiet spot to take in surroundings after a day of hustling around the parks.