That CAN be true, but generally speaking you can just pick the 2nd or 1st best power choice of your own class. There are specific cases where a given class, or at least some builds, have weak options at a given level. In that case its not such a bad deal, but there are plenty of classes where that's unlikely.
It is almost always true with a couple of specific exceptions - and even then, that's usually because a PC wants feats from a class so badly that they don't care about the power swaps. I'm not talking about the 2nd/1st best choice of a particular level - I'm talking about the class as a whole. Each class(for the most part) has about 1-4 truly standout crazy useful encounter options and no class manages to cover all the Heroic Tier choices well - everyone has multiple relatively 'weak' choices in comparison to those 1-4. Even Fighter, Wizard, and Warlord.
Examples:
Quicksilver Motion(Monk 6) - every melee PC who hasn't picked up some other option should want this.
Serpent's Cunning/Eagle's Splendor(Druid 6) - get +1 to hit, +2 to your most useful skills, and either a free skill or a +1 to Will.
Dimensional Vortex(Swordmage 3) - dominate as an interrupt.
Demand Justice(Invoker 6) - opponent made a save? Interrupt and force them to roll again.
Vengeance is Mine(Warlord 1) - opponent attacked you because you had them marked? Hit them once yourself and give a friend a chance to pound them. Or Disruptive Strike to instead negate their attack, especially if Wisdom is your secondary stat.
Mantle of Unity - assuming a well-rounded party, give everyone about +9 total to defenses for a round.
About five different 'make a minor action attack' options.
Rain of Blows - make 3 attacks
Flame Spiral - make 3 attacks
If you can't get something out of there that drastically improves a PC, just wait until level 16 rolls around, where Cloak of Courage(give entire party a surge's worth of temp hit points at the end of a short rest as an encounter) or Borrowed Confidence(roll twice for all attack rolls) shows up.