The Good: Power of Five Orions
The Bad: Why not just use Five Orions?
The Ugly: Took 20 years and millions of dollers to build. While it is assumable that five orions would be the same:
A. More shipyards could assist. The Colossus Was Top-Secret
B. Newer Destroyers could be developed. A replacement to Orions? Slow, but steady. A replacment for the Colossus? Not even possible.
C. In a battle vs. Sahathans, 4 Orions go down. Last one escapes. 4/5 of the cost of the Colossus.
Actually, the Colossus was about the size of three or four Orion-class destroyers, with "more firepower than five Orion-class destroyers." I don't understand how multiple shipyards would help any more than they probably already did; building parts to order and warping them to a central area to be assembled. Though the Colossus is a surprise to the player and their wingmen, and classified Level Rho, its existence was almost certainly known to the GTVA General Assembly, and to the numerous contractors involved in its production, including Nankam Aeronautical, Mesa Corp, Mekhu Enterprises, Johnson Munitions, RNI Systems, Triton Dynamics, Subach-Innes, the Akheton Corporation, Snapka\Flegel, and many more companies which were judged to be of too little importance to be listed in a readable font size. Add that to the mentioned benefits of morale, and the fact that the Colossus is almost indestructible and a sign of progress, and you've got yourself one heck of a justifiable project.