Just curious...why are you not running the most recent version of iOS on the iPad? The one you're using is from 2 years ago. As far as I can tell, iOS 11 is compatible with 10.11.
Generally, unless you have hardware constraints, or serious application constraints, I recommend keeping operating systems up to date. You don't have to live on the bleeding edge and update the day the new version becomes available, but once the dust has settled? Usually a good idea. Of course, those of us facing the upcoming 64-bit dilemma in a year or so will have to make some decisions; I definitely have some 32-bit software that I still actively use and for which I may not have substitutes or updates - including Adobe InDesign and Acrobat Pro. I can buy PDFPen Pro and get most of the capabilities of Acrobat Pro (which is a whopping $450 USD or $15 USD a month on a yearly subscription) but so far, there is no adequate replacement for InDesign and I NEED that. Affinity are supposed to be releasing Affinity Publisher in beta at the end of this month - I certainly hope that it becomes a capable alternative, because I really, really, do not want to have to pay $50 USD a month to use Creative Cloud.
Apparently Microsoft Office 2016 will get updated to 64-bit in the August update - so that's good, as I need that one too.
Depending on what happens, I may have to run a pared down Sierra on an external drive to continue using some apps for specific projects. Not looking forward to that possibility - will get an external SSD if it comes to that, I guess.