Rhodesia
This probably would also have a big impact on the Rhodesian Bush War. Angola had a Russian manned radar tracking system that it used to cover Zambia's airspace for them. Zambia as you may know is one of the main staging areas used for ZANLA and ZIPRA attacks on Rhodesia. With out the radar system the Rhodesian air force could easily penetrate into Zambia undetected and carry out raids on Guerilla camps. This can be to devastating effect as we see in the Green Leader Raid of Oct 1978. The Angolans also gave the Zambians Mig protection in case of emergencies. In addition to all of this inside Angola itself a huge ZIPRA base was located at Luso.
If the MPLA was destroyed and Cuba was not allowed to deploy 20,000 troops in Angola, South Africa would not be as worried about SWAPO and could focus more closely on supporting Rhodesia.
On another note UNITA was very supportive of Mobutu so i don't know what effect that has on wars in the Congo.
