Without a few blank walls, you can't have a streetscape like this:
The Kensington Building in Winnipeg similarly takes a lot of heat for having a big blank wall... but the problem is not the blank wall so much as it the fact that the expected building next door never materialized.
In the case of this building in Regina, if there is any blame to be handed out, you can blame the developer for being too optimistic about the development prospects of the site next door, but that's about it. Had a 7+ storey building been built next door at any point in the last 40 years, all anyone would notice is how nice that block looks. At least the NCO building showed up to the party.