You will have more capacity to expand your empire (giving more Dominance-points) and players whoes empire has been broken, will feel it right away.

and why would that be better than how it is already?

If you want to play by those rules, play Risk.

Would change the game a lot, because part of the strategy is taking risks on putting a territory a territory at risk and hoping it gets dice.

you would get less reinforcements, easier for people to split you up, E.G could finish the roudn with 8 linked territories someone could split em up and then when its your turn ud only get 4 rather than the 8 you would of after ending your turn.. and seeing as you cant place them individually like Risk taking you r territories back again would be pretty hard. And also unlike Risk, you dont get
Reinforcements based on how many territories you got unlinked/linked thus making the game longer and boring. And yes you could briefly Expand your empire but then it would also Decrease just as easy

no-one likes long games, that would make it very long and slow indeed

bad idea. it takes away a lot of the strategy and risks.