While it’s common practice to require a drug formulation to be ordered, requiring a drug formulation at the time of ordering is an implementation detail, since the formulation can often be inferred. For example, if the person filling the prescription (e.g., the pharmacist) knows the concept (amoxicillin) and the desired dosage instructions (500 mg twice daily), she can figure out what drug formulation (either one 500 mg tablet or two 250 mg tablets) to dispense.
But also, these are order templates (not drug orders). Even if we make providers order by drug formulation, if the are fives forms (e.g., five strengths) of a medication that are all typically ordered as “1 tab by mouth once daily”, a single template linked to the underlying concept could be used as the default template without having to manage five templates to accomplish the same thing.