Tomorrow will be my second international flight in March post merger; my husband has also flown two international segments. We are 0 for 3 now for upgrades. The likelihood of an upgrade for me tomorrow is poor, despite being a 1K on a Y fare. Since I have a refundable ticket I can use different routings with connecting flights, but no there is not one available European gateway with an available upgrade. On top of that, I can't seem to maintain my economy plus seat in the row I want, and United hasn't returned my unused system wide upgrade or my husband's miles. At this point the benefit of my 1k status appears to be United drink coupons (I think they actually come with silver premier status) and less time on hold to resolve constant problems. Agents sympathize with my plight and several have told me to complain to United. I will try again but so far the customer service complaint route has proved totally ineffective. I am disheartened (and dreading tomorrow's flight).
At this point, you don't want to look solely for upgrade availability so much as flights with a lot of seats left in biz class.