Final answer:
The classical waterfall model requires full anticipation of the end-product, risks including unnecessary requirements, and suffers from inflexibility due to strict phase separation. The spiral design process offers iterative improvements but demands careful resource and time management. Structured decision processes help ensure optimal design solutions.
Step-by-step explanation:
The disadvantages of the classical waterfall model include a few key points. First, the end-product must be fully anticipated from the outset, which can be problematic since requirements often evolve during the course of a project. Second, some requirements may be defined at the beginning of the project but turn out to be unnecessary, leading to wasted efforts and possibly a solution that does not fully meet the customer’s needs. Third, the strict separation of phases can impede flexibility and adaptation as the project evolves.
A better alternative can be a spiral design process where design improvements are made iteratively. This method enables continuing evaluation and refinement, which often results in a more successful product. However, this process requires careful planning to account for the time and resources needed for each iteration to avoid delays and budget overruns.
When using any structured design process, it is crucial to evaluate solutions against constraints and criteria to ensure that the best design concept is chosen for product implementation. This evaluation should involve a structured decision process to reduce the likelihood of overlooking important aspects or making poor design decisions.