Chances are,Azerbaijani-Armenian tensions could still flare up over Nagorno-Karabakh.
Also,in Georgia,you'd have the Abkhazia and South Ossetia stuff eventually so chances are,the TSFSR might be able to survive during the USSR but upon collapse in 1990,it will fall apart.
The Soviets could probably keep it together through brute force if they really wanted to,but honestly dividing it up was probably their best bet at taking that territory.