What you’re referring to as far as being useful at level 1 is what I’ll typically refer to as “power spike levels”. For casters, that’s every new spell level unlocked, for martials it’s when they unlock extra attacks, reliable expertise is a big one for Rogues, etc. it’s bad if they’re excessively delayed and the character is only spiking at level 10,11,12.
That being said while your comp is fine if going single Class only (though I’d argue it would be better served with a Rogue instead of a Barb), it’s also the perfect example of the power of multiclassing. After all, if you go Sorc and/or Cleric on your Wiz after 2, you don’t actually delay your power spikes at all, and the amount lost is absolutely minimal Vs what you gain. You’ll still be casting 5th level Wiz spells at 9, etc, just with more going on besides.
It’s not typically as free to multiclass as it is with Wizards, but still, the point remains. Same deal if you did want that Rogue and were permitting multiclassing. Even if you prefer pure Rogue for Invis at will and reliable expertise, those are at 9+. Knowing your power spike levels, it’s then basically free (well 100G) to instead go Ranger 5-8, get a lesser invis going early and an extra ambush attack etc, then respec once the additional Rogue levels actually result in a payoff.
