I have similar experience for award availability compared CO to Delta. I am also CO Gold and no status on Delta, but Delta is much easier to get partners' award seats while CO is quite difficult. However, I have no trouble to get CO's BF to Hawaii (from LAX) while it's very hard to get Delta's less attractive F to Hawaii.
My guess is CO is new to Skyteam and the agents are less familiar with Skyteam awards. OnePass still can't get me a F on Air France, but Delta could. It takes only 140,000 Skymiles to fly LAX- Taipei, either on China Airlines, Malaysian or Korean, while it will take 200,000 OnePass miles to fly F on Eva to Taipei. Co is weak on partner award compared to other airlines.