Usually always more than one way to get from point A to B. While I've been through Doha a LOT while on active duty assigned to HQ CENTCOM (Qatar is the Forward HQ), I haven't been thru there since 2009 or so. Was and as far as my still active duty friends say, it is still safe. I've looked at using Qatar Air for going to Namibia but haven't actually done it yet. The upside for Qatar Air for Namibia, is it's one overnight flt to Doha, a long 10-12 daytime layover in Doha and then a 10+ hr overnight flt direct into Windhoek that arrives I think early-mid morning of the third calender day of travel.
The down side of Qatar Air into Gaborone Botswana, while your particular departure flt from DFW gives you specifically a shorter layover in Doha, others trying to connect with Qatar Air US hubs may have longer connections/wait times at those hubs and at Doha. Then too, as of now, the Qatar Air flt doesn't arrive in Gabby until after 5pm so you'll be spending the night in Gabby before being picked up to meet the others coming in from J'berg on Air Bots just before noon the next day.
Shots - none "required". Is a non-malaria area so no malaria meds required. No testee flies. No GD mopone bees. Hell, only saw just a few bot flies. There are a few ticks and a few scorpions. Only "shots" I usually recommend it making sure you've had a tetanus booster in the past few years because like ol' Rooster Cogburn (John Wayne) said to Ms. Eula (Kathrine Hepburn), "be careful out there Sister. Everything out there will either bite ya, stab ya or stick ya!". I always take a 60-day supply of doxycycline just in case of maybe tick bite fever. In 14 years, only caught malaria once and that was in Windhoek in early April during the rainy season.
