As I said I have not used them enough to really know how the G43 fares against Allies. But IF they need a buff, it could be a small durability buff to let them close in a bit better and better fulfill their role. Sprint could work similarly
Yes for the role of g43 aggressive usage sprint and durability are nice things I agree but nature of grenadiers will be broken. They need to be work with HMG to get achieve things not really by themselves...
As for the G43's they gives nice DPS to targeted inf with High accuracy shots ,rate of fire, moving accuracy at close to medium range but when Allied LMG's (esp BAR's) come to play not really viable to use than LMG 42.
Like I said before , in my opinion if we gonna buff g43's giving accuracy bonus to light cover or suppressed inf , it will be fit better to the role of grenadiers.