10Man was overall still harder in Cata than Wotlk.
After all, the consolidated the split between 10man and 25man there.
In Wotlk, 10man was pretty much inferior to 25man in terms of difficulty / loot (altough one can debate over the difficulty of 10 man heroic and 25man Normal).
That's reflected in the Ilvl of the loot, taking ICC as example.
10Man Normal 251
10Man Heroic 264
25man Normal 264
25man Heroic 277
In Cata, it was changed that normal drops normal Ilvl regardless of raidsize, so 10 man Normal was tuned to be in line with 25man.
10Man Normal in Cata was not equivalent to 10man Normal in Wotlk, it was harder.