People have been telling stories for a long time, and more importantly, people have been listening/reading/watching stories for a long time. Audiences tend toward specific structures/devices/methods for a reason, and while the "why" of such tendencies are certainly open to interpretation and debate, "what" they are is a bit more concrete. You can try to "mix things up" by switching tenses, point of view, etc. Lots of authors have done so, with varying degrees of success. Thing is, if you play with conventions, it's going to be jarring to audience immersion. Shaking things up can be a good thing, but it must be handled delicately for it to have its intended effect.
It's your book, and you can do anything you want with it. The stories most often touted as "brilliant" often flout convention, but the reason there's so few of them is because it's very difficult to flout convention and still keep your audience at the same time.
I personally dislike books that switch between first and third PoV's, and I've yet to find an example where the same effect couldn't be achieved, and better, without resorting to that particular conceit, but that's only one person's opinion.