Picking a good class combination makes the game go from almost impossible to trivial. If you're struggling at any point you can change your class in the same menu where you learn new skills.
Yes Thief is not optimal for some of Laura's quests but changing class should solve that too :p
Some destinations are better suited for certain play-styles. I don't think there's any build that does well everywhere.
Thank you, I'm really glad you liked it <3
If you have more questions you can ask me or a more veteran player at https://discord.gg/r2aRAgQ