It is still common practise in this region (The Middle East) to ask for designs to be submitted along with RFPs or pitches. Here I attempt to explain why this is a really bad idea and is essentially a lose-lose scenario for everyone involved.
As Paul Boag says in this related blog post, website design is a process.
Arriving at a design for a website is a process rather than a flash of creative inspiration. A whole range of factors influence how a design develops and none of these steps are present in speculative work.Paul Boag
Factors That Influence A Good Design
In-depth research and understanding of your business objectives and success criteriaTarget audience research, competitor review and analytics analysisInformation architecture, site-maps, wire-frames and usability testingImmersion into your brand, tone of voice and brand guidelinesConsiderable collaboration and iterative creative evolution
Waste Of Time & Money
None of the above factors come into play during a pitch or proposal. Any design work done without first doing any research or wire-frames is a waste of time. The resulting designs are not properly informed and as a result have no value other than looking pretty and demonstrating that the creator knows how to use Photoshop.
Not only is it a waste of time, it's also a waste of money. In order to stay in business every company needs to recover their cost of sale. This means that if you ask for speculative design you're spending more than you need to because you'll end up paying for it in the end and seeing as the design will not be properly informed, it will most probably need to be discarded and hence result in a waste of money.
Whereas speculative design focuses on you the client, proper design focuses on the end user
In short, speculative design favours superficiality whereas good design is a collaborative process between you and the designer. The designer needs to have a full grasp of your brand, business drivers and user requirements. Good design only emerges after numerous iterations and multiple rounds of site-maps, wire-frames and user testing. Whereas speculative design focuses on you the client, proper design focuses on the end user. Good design is about facilitating the user and enabling them to complete tasks easily which requires research and planning.
The main reason for asking for speculative design is to be able to assess the capabilities of the designer or design agency. You don't need speculative design for that, a thorough review of their portfolio of existing work will be able to answer that question. Another way to know if a particular designer or agency is suitable is to speak to their existing or past clients. You'll soon find out if they are happy with the service they received and if their website meets their expectation and business objectives.
I hope this goes someway to explain why speculative design is a bad idea and should be discouraged. Check out the NO!SPEC campaign for more information.