Is it too much? For what be my first question? So you have your perfect reef in your head, what does it look like? Is it going to have a little of everything or just Softies or LPS, maybe some anenome or all SPS?
The term "turnover" is a tool that is used to describe ones flow, better yet brag, about it......speaking of which, I added some more so mine is a little more than the 70x shown.....

......its simmilar to the "watts per gallon" rule used in lighting guidlines. So, don't get caught up to much into it as a "rule" and is more about quality than quanity. ie: laminar flow vs random flow. The subject in itself is something we get caught up in like chasing the "perfect" bulb that will give perfect color and intantanous growth.
Why does what you want to keep matter?
In the SPS world for example, there is never too much flow......some tanks have so much the sand blows around and clouds the water, hence why Barebottom tanks are so popular with that crowd.
Flow this high can rip polyps off of LPS and bend softies like trees in a windstorm. Both of these reasons are why I have a Barebottom, SPS only tank.
Quality of the flow and the randomness is important as well, you can play with the angles of the powerheads to achieve the best pattern for your corals as flow is how corals eat and breathe.
The short answer, no......in fact I would think it would be about perfect for most tanks and may even suggest getting multiple smaller models to increase randomness and eliminate deadspots and different flow combinations as needed.
I would like to play with a gyre system using a controller to obtain the back and forth surges in the ocean.
Research your livestock you want to keep, and do your best to simulate that enviroment in your tank.