Agreed - individual mods don't do squat. The mods are intended to reconfigure stock system to a racing system and are not intended to address specific shortcomings in any one area.
That's some of what's causing disagreement though, is that some steps are being discussed in isolation, and the reasoning invented to explain the steps just isn't accurate - even if it's a 'good' step to take toward reconfiguration, but no single step does much good (except for using a larger pickup and opening ALL the passages associated with the pump and filter - those should be made yuuuuuuge with respect to cross sectional area).
Just drilling the mains feeds larger is likely to cause more problems than gains. But do it AND block the cam feeds (restrict) and you've likely helped balance flow to some extent. Restricting feed at the #1 to the opposite lifter bank goes along with that.
But none of theses steps or reconfigurations is done to eliminate velocity. They're done to eliminate leaks PRIOR to feeding the mains. By doing so, the pressure available to the mains is retained and only drops after them, not before. That's basically what all the racing blocks did - they feed the mains first, the mains feed the cam, and the lifters are fed from the last cam feed. That last cam feed determines the flow potential to everything that's not a main bearing, and so chances for catastrophic oil pressure loss at the mains is reduced.
