Perhaps - it's hard to say. (The project was Google's Authorship program.) The product would've been a very different one without it. We had designed a federated system that worked at the level of the Web and let any website serve as an identity provider. In theory, this was going to change how the web worked, and that change would also be accessible to other search engines and spiders. We didn't accomplish that. The request to make it only work with G+ basically involved restricting that system so that one of the URLs must be "plus.google.com".
OTOH, this did subsequently simplify the system a lot, and enabled follow-on features that wouldn't have been feasible under the original design. Our original design defined an author as a clique of webpages that all linked to each other using rel=author|contributor backlinks; defining a primary key is challenging in this situation, because you have to carry along the identity of the clique throughout the system. Requiring G+ let us key everything to an author's Google login, which then opens up the possibility of other systems using that data easily. It let us display the author's profile picture (which was the primary "boon" to get authors to participate), and connect their works to their G+ profile so they could easily advertise everything they'd done. It helped in marketing and using the product, because basically nobody outside Google (and only like 4 people inside Google) actually understood the author-closure stuff.
Understand, also the historical context behind this. 2011 was the year of "Open systems lose." Android (the open-source operating system) was playing catch-up to iOS (the closed one), and arguably only caught up because they were willing to close off much of it. Facebook had used GMail's "download contacts" feature to populate their own social graph, and then systematically cut off every attempt to crawl their own, also disallowing users from exporting their friends list to Google. OpenSocial had been trying to gain adoption for 3-4 years and failed so badly that Google+ was necessary. OpenID was dead-on-arrival, and Facebook Connect was taking over the web. Google had just sunk two years into providing real-time search of Tweets, only to have Twitter pull the plug on the deal and sink the project.
So in hindsight, it's difficult for me to say that the execs made the wrong call. I was kinda ambivalent at the time - I wasn't pleased, but I could see the reasons behind it and agreed to help out with the implementation. A number of my teammates were furious and quit the project, moving to other departments.