Thanks for the feedback guys, I was particularly keen to see how people would try and abuse this.
From some more discussions with my gaming group and the feedback from people here, I'm not convinced the proposed change is too OTT but we'll have to see how it fairs in some field testing.
The examples above from GlynG are ok, and would make for a devastating barrage but in doing so the Titan example looses a lot of effectiveness against other WE and potentially RA formations as well due to lack of hits in comparison to the standard warlord.
The arty example of mixed bombards and Manticores is also good yet wouldn't consistently shoot more than 8 BP a turn and would be limited to 90cm whilst the stock standard 9 x basilisk can do 9 BP a turn, fire directly if they hold and have better armour so I think its a fair trade.
As Kyussinchains points out - the barrage table is wack anyway, any super BP barrage with lots of rules is still generally poor compared to an equivalent points value in direct fire weapons because you loose out as the BP trend higher.
Cheers for you wisdom Onyx - and for tournament play - I do agree KISS for now.
(I see what your doing.. trying to keep the good stuff for the iron warriors.. I'm watching
)
My intent here would be a tested optional or alternate rule like the aerospace optional rules or the CAP a CAP action that many people employ that could be offered to players as a tested option.