I seem to recall that the main reason it was aborted was that some meetings became very one sided, and therefore boring to some, and there wasn't an opportunity to pull those points back by introducing a tactical.
One part of being a fan was trying to pre-empt the Team Manager's next move and that essence became obsolete during that short trial period.
Over the years the BSPA has tried all sorts of initiatives such as different heat and race formula, different numbering, six lap races etc but at the end of the day all the average fan wants to see is competitive racing on well prepared tracks with easy to follow rules that are consistent within each league...which hadn't always been the case (different number of heats for example) making it confusing to the average fan.