The TWW system use a separate unitName for each player. In TWW there are over 40 (and counting) different units for each major player (6 plus 3 neutrals). 300+ Units, and their definition/attachments (also the long list of givesMovement under docks and airfields (which could be handled by a movementBonus tech assigned at the beginning of the game)).
For a complex map like TWW, this maybe the best way to achieve technology gains (although a combination of both may help to reduce some of the duplications). But for a map like @CrazyG HoH, where @CrazyG has expressed his disinterest in this type of technology tree, the expansion of the tech abilities may be useful.
@CrazyG in HoH as thought about splitting up the 'Navy' unit into two different units. A transport with combat capabilities, the other a warship. If he wanted to add a tech to made the warship a multi-hit unit, his only option now is to go the TWW route, where as a hitPointsBonus tech ability would give him another option.
TWW is a great map, but to state that its Technology/Research system is the 'best' may only be true for very complex ideas. Simpler systems may want a simpler approach.