Yes something like Fighter, barbarians or Paladins are usually stronger on lvl 1 but I don't think Wizard will be useless.
At lvl 1 something like a sleep spell or color spray is very powerful (no save in 5e for both) against something like a horde of goblins etc
The main point is that wizards get emptied pretty fast so got no endurance but you can always rest more often if the game does not force 5 encounters on you which goes against freedom of decision making anyway
With the systems BG3 is using and especially the high focus on verticality and overpowered bonus actions this makes some Wizards spells better than usual.
Lvl 1 Grease, Thunderwave, Find Familiar I can see being stronger than normal 5e
Lvl 2 Web is probably stronger, Ray of Enfeeblement is good against strong melees (half damage no save first turn) if you get easy advantage through more verticality
Fire Bolt Cantrip (as well as Mage Hand) will make you be able to easily interact with all that environment stuff that your overzealous level designers probably put everywhere to interact. High ground for advantage to hit well and it has nice 120 feet range.
When I GM DnD theres no barrels of explosive oil everywhere (and similar) that a wizard could easily interact with but I can assure you the density of that will be higher in this game.
At lvl 5 theres no problem anymore anyway because strong spells like Haste, Fireball and Hypnotic Pattern become available.
So its really only the first 4 levels that Wizard would have a problem and its not really the case because even then there are strong spells as explained above. Exact strength will depend on the precise implementation of all spells ofc and how often the game forces you to not be able to rest to get your spells back.
Last edited by CyberianK; 13/03/20 10:27 AM.