[@Norschtalen]
Well, it is a 1d4 and only a 1d4 per target and only as long as the spell lasts... and there definitely are more powerful options when it comes to concentration spells. Well, not this early, but Bless is supposed to be good early. Perhaps the DM's have been afraid of it being too powerful, but the wording is clear especially when compared to the Bardic Inspiration it resembles: The BI specifically states that it is for one die only. If they wanted to limit Bless and/or Bane, they would have stated that in the spell description. The errata has nothing on the subject either, so I do not see why it would not be used as written.