“Silty loam” contains a higher proportion of silt than the common 40% sand, 40% silt, and 20% clay. Is this imbalance always a bad thing?

Always; high silt soils drain poorly.
No; higher silt levels are usually preferred to the common balance.
Sometimes; however, some crops thrive in soils with high silt levels.
Yes; high silt levels make the soil infertile.