I think you are missing a few datapoints:
1 - We do not know what kind of demands Destiny (or the next Battlefield) places on a system
2 - Having equal resolution could also mean that the XB1 version made other sacrifices (lower quality AA, lower resolution shadows and reflections, other missing effects)
3 - As usual the XB1 version may have sharper frame rate drops in the more demanding scenes or the XB1 version of a game may target 30 fps and the PS4 target 60fps (like Tomb Raider:DE)
All in all I can't doubt things improved for the XB1 version of cross platform titles, but it remains a weaker machine... however it does seem like the differences are less stark than they were early on! which is great for those that have this machine...
Still, have you seen Uncharted 4? Infamous:SS? The Order 1886? all the first party AAA Sony titles look miles ahead of anything crossplatform or dedicated to the XB1, not only that but they perform really well on the PS4 too!
