Scaling is a huge issue in kaw in terms of BFA/bfe.
For an example, back when I played Final Fantasy 11 online, static numbers from equipment scaled down if you chose to wear high level equipment in lower level capped events and PvP.
This could be easily implemented in kaw by assigning tiers for build CS and adjust BFA/bfe along that scale accordingly, but the major flaw with bfe still is it's weight vs hit ratio factor; which is 0.
Both BFA and build CS effect hit range, why does BFE not do the same? It's being added to the matching equation yet only offers a static number which does nothing for plunder or hit range. This was the biggest flaw with including it in matching, which made it the easiest to exploit in S3 and beyond, giving ssh/msh more exploitability by allowing them to be even stronger in raw numbers, yet have no negative impact on plunder leaked.
Tl;Dr version:
-scale bfe/BFA with build cs,
-balance all matching factors equally,
-make builds pay their actual strength (with a min/max cap)
I'm sure there are a few flaws there, but with so many great ideas that always seem to fall on deaf ears, more and more veterans seem to wander off to greener pastures while the developers sit silent force feeding us promises of improvements and EB events and HTE o'plenty.