One thing that is often complained about is that the random mission generator keeps popping up the type of missions you don't want, often repeatedly. Another one is that you find too many batteries and not enough "neat" loop.
All these aspects are ultimately random. So if we see a mission repeatedly in a Cluster mission, it is just like rolling 3 6 in a row with a die. It just can happen. Dice don't have a memory, the likelihood of rolling a 6 is always the same. And the same applies to the random generators in most programs and games.
But - it doesn't have to be this way! You could give the randomization elements in STO a memory!
How would this work:
For exploration missions, it would be simply this way. The random generator might store the last few missions you have done. When "rolling" from the available missions, he will exclude all missions with the same mission type you already had. (Unless you already got all mission types).
For Tribble, it would be cool if we could set the type of mission the random generator will look for, but even this will be better than pure random selection - since you just have to enter and leave missions until you get the one you wanted.
Loot is a little more difficult and might ultimately not be as useful.
As I understand, the system is set up so that every loot category (if it is available at all at your tier), there is a random roll on each drop. (So you could get Batteries, White, Green, Blue and Purple Items all in one drop - but the chances of that happening are low.)
So, there are two ways.
Either you simply exclude a roll for a particular category if it has come up the last few drops. Or you exchange that roll with a different type of drop that hasn't happened yet. (This would mean, if you have found a battery, you won't find again the next time, but the likelihood of finding a green drop is higher. But it would also mean that if you just found a purple drop, the likelihood of doing so again is less likely)
Alternatively, the system just looks at what kind of item at that category just dropped, and ensures you get a different one. The latter might not be such a spectacular effect, since you rarely get the same drop anyway.
NPC Spawns in a mission
Exploration and Sensor Cluster missions cause random selection of enemy ships or NPCs to spawn.
The last few spawns could be stored so that every enemy group will look different (within the range of available spawns.)