One of my players is unhappy with his character and wants to change

So, we've been playing our second campaign, and it's going great. We're a group of four, currently on our fourth session, with everyone at level 4. The players are fantastic, and everything is running smoothly.

However, one of them, who plays a dwarf paladin, messaged me saying he’s not really enjoying the class. It’s not playing out as he envisioned, and he was expecting more complexity. He’s considering switching to a druid and asked if that would be okay. He also assured me he’d work with me to give his current character a proper send-off without it feeling rushed.

I’ve allowed PC swaps in past campaigns and could do it again, but I don’t want it to feel too easy—like something you can do anytime, as if it were a video game. That said, my priority is making sure my players have as much fun as possible.

I suggested he take another look at the paladin’s future levels to see if he gets a bit more excited about the future of his PC. If not, he can come back to me, and we’ll figure out a smooth transition.

What would you guys do?

TL.DR: A player feels his dwarf paladin lacks complexity and wants to switch to a druid. I’m open to it but don’t want swaps to feel too easy. Suggested he check future paladin levels first. If he still wants to switch, I’ll help with a smooth transition. Thoughts?

EDIT: Sooo this got waaay more comments than I thought it would haha, thank you so much to the ones that gave such good advices, I'll definetly keep all of that in mind and I will talk to my player. Thanks again for this, I'm just getting started but love the community already!