OP,

I'm firmly in the 'ride it a year, then figure out what you want to change (or 'upgrade') -- if anything' camp.

That said, there might be some initial/early changes you want to make, but these are not for upgrade reasons but rather fit/comfort: contact points. These are i) bars/grips etc; ii) saddle; iii) pedals.

Bars and saddle are obvious; you may or may not find the stock saddle comfortable, and you may or may not find the stock bar configuration quite right. You might find yourself wanting to change these, but I'd certainly give even that a little ride time so that you get a clear sense of what you might find preferable. Pedals? You might like the feeling of control etc. with clipless -- I do, but don't go clipless with the idea that doing so will make you 'faster' -- it won't. So pedals are discretionary, to my mind.

The other thing is tire choice. There's probably nothing at all wrong with the stock ones, but they are likely heavier and have more rolling resistance than many up-market tires of similar size and puncture-resistance. So that is an initial or early change that would make sense -- but unlike (i) and (ii) above, that's to my mind a discretionary as opposed to necessary (fit/comfort) change. You could easily wait until the stock tires are due for replacement and 'upgrade' then.