The only time I don't think it's necessary is for Untrained skills, where you get better at things you really have no business improving. +1/lvl to untrained is only necessary if all checks nonsensically scale with character level, which we're promised they shouldn't.
My concern in that regard is while there may be nothing in the rules about non-sensible scaling, the people doing the adventure design will do such scaling under the idea that skill use should challenge the players.
Like the mayor the characters try to convince at first level is equivalent to a third level character, but the same mayor when dealing with tenth level characters is now equivalent to a 12th level character. Or that the wall of the fortress is now built of smooth adamantine instead of rough-hewn rock to make climbing it more difficult, simply to be difficult.