We've made significant advancements in our understanding of inflammation in general over the past couple decades but much is still to learn. We've known about about the risks of corticosteroids for a very long time now and in many cases they can be disabling. What isn't as clear is the long term risks of the COX inhibitors and the risks of inhibiting inflammation systemically.
Gastro, cardiac, hepatic and kidney damage are all well known risks of using COX inhibitors such as Ibuprofen and Diclofenac. The latest research focuses more on systemic inhibition of inflammation as opposed to specific drug effects.
There's so much more to learn on this topic but among the more recent discoveries are the following:
Delayed wound healing, disruption of immune system surveillance (the bodies way of monitoring the health and identity of cells in the body), an increased risk of infection, effects on bone (and even cardiac) remodeling, muscle atrophy (a big no-no if you have chronic pain), metabolic effects (think insulin resistance) and finally, the big one: Mental health effects.
I think more then anything, the consequences of inhibiting inflammation on a persons mental health has been discussed more then any of the above. We see an increased rate of mental health issues in those using anti-inflammatories for extended periods of time although it is mostly correlational and far more work needs to be done on this topic.
When you think about it, this is all really obvious. Inflammation is integral to healing the body (and brain). Cells detect an problem in the body, inflammatory cells travel to the site, and through a complicated process of various mechanisms, the process of healing begins. Clearly systemically inhibiting this process isn't without risk. At the end of the day, like all medications, its up to you to way the pro's and con's. It's more difficult to do in areas like this, because the risks arent entirely clear.
Either way, if Ibuprofen makes your life that little bit easier, i'd say take it. Also, 3,200mg per day is infact a lot. In my country, clinical guidelines are clear that the maximum dose is 400mg every four hours or 2,400mg per day. I think even this dose used for potentially decades is too high.