BOAC, i have heard all these argueements before re having arm engaged. If Boeing are uneasy about it dump it. I have seen over the years different angles trying to operate the 737 3/4/5 and mainly these new ideas come from new operators/ charter outfits. Alot of charter outfits started to use N1 and a click at 1500agl so the bug would drive to plus 20. I would go into it here but by doing that one is leaving them selves hole open for many scenarios as against keeping it simple as per what boeing says by selecting what they recommend as against some new ideas by non boeing test pilots. Flying 737s is a fairly uncomplicated business that can turn into a can of worms when the test pilots get their paws involved.
Capt Bear