They're both level 1 abilities, ad_hoc.
Bardic Inspiration scales on it's own, Bless can scale with the use of higher level spell slots.
Wish is a 9th level spell.
There really isn't an equal comparison of a natural 9th level spell to an upscaled 1st level spell up to 9th level, or an ability that scales.
Should any 6th level class ability that can cause damage be equal in impact to a fireball or be considered sub-par?
Should any 5th level class ability that deals with movement on its own be equal to fly in impact or be considered sub-par?
Should the gains from an 11th level class ability that deals with damage be equivalent to disintigrate or be considered sub-par?
again, the method of trying to determine balance comparisons by comparing one element of one package vs another element of another package across classes should not be taken as a valid approach for judging whether or not a boost is needed to an element or an ability. There are a lot of elements that go into a class.
I mean, lets see - clerics get two skills from a limited number of skills while bards get three skills from the list of all skills. Does that mean that c;early the cleric is under-skilled and should get their skills list changed and slots increased? Fighters get d10 HD but wizards get d6 - obviously that needs to be changed too?
In the two cases above, i was comparing apples to apples - specific sub-elements to their exact equivalants - , not apples to squash (a spell vs a class feature.)
Obviously, as a GM one is free to alter classes as they feel is appropriate and add or subtract whatever they want as long as their players consent to the changes but in this case the attempts to support this as somehow an objective need, a showable imbalance, etc are not compelling or even based on a sound comparative foundation.
The YUGE change in bonus actions for a boss fight and the gains of the inspire dice across party from round one the "spend all at once" rule change would create seems very much a significant and overly strong improvement to *not* the inspiration die itself but to the bard overall - freeing three or four bonus actions to the first five rounds of big fights.
I just do not see that as an established need supported by any evidence of bard class weakness overall and find apples to squash arguments to be more or less auto-fails as far as being convincing of any balance assessments.