you should review the replay first before complaining.
The enemy Zeus near the Banisher had the very same firing problems, on several occasions even. It might have something to do with the trees around or perhaps something specific to that map.
Secondly, those Banishers killed 2 coms and a bunch of other stuff even when used quite recklessly. You wouldn't suicide Warriors or Levelers into Zeuses and defenses so it doens't make sense to do that with Bansher. After watching the replay I would guess they still made cost even when used wrong and against their type counters.
Things to keep in mind about the new Banisher:
It is 33% cheaper than the old one, which is a huge deal.
It is a RIOT. It does lose to assaults, skirmishers, porc. Do not expect it to work great against its counters.
That said I don't expect this Banisher to be perfect balance wise. Maybe it could be a bit stronger, maybe it is fine. More science has to be done.