To make code more type-safe, it would be nice if existing built-in attributes/methods that currently only accept a constant or string get an overloaded version that accepts an Enum.
BUFFER ttOrder:FILL-MODE = "MERGE":U
BUFFER ttOrder:FILL-MODE = FillMode:Merge. /* Strongly typed */
BUFFER Order:FIND-BY-ROWID(orderRowId, NO-LOCK, NO-WAIT)
BUFFER Order:FIND-BY-ROWID(orderRowId, LockMode:NoLock, WaitMode:NoWait). /* Strongly typed */
Other examples could easily be added.
Another one that comes to mind are attaching event procedures. These strings are long and typing errors can be eliminated significantly with proper ENUM objects.