I think Keim's goals may have shifted, but I don't blame Arians necessarily. In the Arians years, we were looking at a strong roster with very few holes - we had very few positions open, and therefore taking a risk on a guy with amazing measurables was much more sensible than some guy with basic football fundamentals who was just going to end up being a backup. Not to mention, we had to focus on the few positions where a guy might see the field, since we didn't have the cap room to fill some of the holes we had.
In the past few years, we've been talent-less, and now everything is a hole. That makes it easier to just take whoever fell to your spot.
This may very well have been true so it makes me wonder why they didn't try to swing some trades that would have position them to select better prospects to fill holes that would have been happening down the road and keeping the roster filled with better players who would be ready to set in when the time was right. Draft less players but get better overall talent.