You might have Heca, but you don't have the WS to actually take advantage of it. Evis has no STR mod only a DEX one.
You forgot about Mordant Rime.
Also, why are people even bothering to argue against Brd melee in situations where it may be approprate? It makes little rational sense for someone to turn down the free damage contribution such that the bard's ordinary dudies are fulfilled. It seems as if this matter is less about the bard as it is about sheer egotism.
I'm guessing because not many bards play outside of that box that they have grown quite comfortable in.
Addressing the Hecatomb gear being bad
(lol seriously wtf?) for evisceration...I don't really know how to argue with that. Many of its pieces are the best evisceration gear pieces in the entire game. Brd can also use some decent WS pieces in place of heca...Osode, Relic Body (have you SEEN the stats on this thing), Kitty pants are pretty good evisceration pieces too.
Anyone that says Hecatomb gear is not great gear for evisceration just doesn't know what they are talking about. Not only do they have some of the largest amounts of DEX on a single piece gear for their slot, but also great chunks of STR...which is great for multi hit WS like this.
Blau is an amazing dagger, great TP options, Great WS options, dagger merits, piercing weak mobs, self tailored songs...I honestly don't see how one could intelligently argue against this.
A well geared DD bard, singing himself Mad/Minuet and getting double marches while eating crab sushi/pizza is going to be a meaningful increase in kill speed. Mobs dying faster = less time for them to hurt the dd's = less MP strain on the mages = easier, increased xp/hr.
After a certain point there are so few ways to meaningfully increase XP/HR. Adding a good chunk of DD from the second Bard is a great way to get this done.
Just because YOU'VE never done it/tried it/thought about it/wanted to do it, does not mean it is a bad idea.