[In response to a question on #SPYAM I wrote this update of an article form 2010 titled "The Relative Effort of SharePoint 2010 vs. 2007." -Eli.]
SharePoint is the best demo-ware ever, and that is why it is a multi-billion dollar product. It’s like going to the pet store and seeing a great dog that does backflips all kinds of tricks – and it really is a smart dog and it does all those tricks – but when you get it home you realize that what you need is a dog that hunts. SharePoint can be trained, but is fundamentally a platform where Microsoft's first priority was first to get the foundations right - to make it trainable and extensible, and today their priority is to make it work and scale in the cloud - their cloud.
If Microsoft's O365 scenarios are not your scenarios, then it is again time to fill the gaps with custom solutions and Apps. You need an experienced architect because solution design matters. You need to know what infrastructure you need to support your solutions. You need to know what components are out of scope for your business case so you do not provision needless infrastructure. If you want a hybrid of cloud and on-premise in any way, you need knowledge of both.
And fundamentally, you need to understand what specific business need you are solving so an appropriate solution can be delivered to meet it. "We need SharePoint" always ends in low adoption. "We need a generic template that works for both per-client CRM and project execution" always ends in low adoption. "We need a website where we can share shedules and designs with clients to support construction projects" is a specific need that can be designed and delivered. Solutions with a concise purpose and audience are seeded to succeed.
SharePoint is complex. There is no substitute for the knowledge and skill needed to design and deliver efficient, maintainable, and extensible solutions. If we were talking about a brand new paradigm with its own model - like when Facebook or Twitter were first released - I might agree with your executive - go ahead and kick the tires. But we're talking about your business, so unless you're okay to proceed out-of-box and without any competitive advantages, that dog will not hunt. Get some experts on your team.