U2 vs Global Hawk is like C-17 vs C-130, to say it's an either/or decision is a huge over-simplification. While the two missions have some overlap, there is significant area within each mission set that is exclusive to that aircraft. To lose either is to lose some functionality that the other can't provide, yet the article doesn't cover that at all. The Global Hawk does have significant issues with functionality, but the Navy BAMS shows promise to fix quite a few of those issues.

To maintain the full spectrum of capabilities, the decision is what mix of each versus which one. If there is going to be a either/or decision that is going to be made, the decision needs to be based on the most likely/most critical future role that we want the asset to fill, not which aircraft flies higher, etc. For example, who cares how high an aircraft flies if the decision-makers determine that the most critical requirement is 18+ hour endurance or payload capacity that exceeds X pounds, etc. For that article to have been a true intelligent essay geared towards decision-makers, the majority of time should have been spent discussing whether the majority of the future requirements would be imint vs sigint, permissive vs non-permissive, responsive vs enduring, etc; then the best aircraft that best matched those requirements would be evident.