2) Make the Final Battle Awesome

The final battle in XCOM 2 was... underwhelming, to say the least. It certainly wasn't difficult. Even on Legendary difficulty, it was neither a great challenge nor very awesome. It didn't really feel too different from a regular mission. Nothing really shone about it. It wasn't action-packed, wasn't impactful, did not shine.

Well, what could the developers do to improve upon the final battle? It would be amazing if for the ending confrontation, we could bring our entire legion of soldiers to battle instead of the standard squad of 6. 

Sort of like the ending of Mass Effect 2, where your entire cast of companions had to work together on the same mission and would live or die depending on your choices. It gave your actions true weight. A single mistake could cost countless lives, and your team is depending on you to get them back home safe.

The AI would scale to match the amount of soldiers we brought along with us on the mission, and we would have to dedicate ourselves to controlling each of their individual movements in a huge battlefield. Everything would be tense. The scale would be large. You would truly think that the fate of the human race was at stake - and that moment would define the epicness of XCOM.

 
The Avatar Project.