First of all, those chords really have no other way to play them. It is awkward no matter what, but what Rakhmaninov did is the least awkward.
I have quite large hands (C-F# and middle notes) in which case this particular preludes comes rather easy to me...
I don't think it's awkward at all!
It's completely fine to experiment, but don't make it sounds like "he did it because he's just because."
Personally I'm not. Or at least I didn't. Point is that the guy made a thread about it, asking why the cross-hands section is written like that and if he can alter it. The apparent reply from most is that no it's not ok, because:
a. This is how Rach wrote it
b. It's easier this way.
c. Voicing sounds better/correct this way.
I agree with all three sentiments, but I didn't get a vibe of "I'll do whatever I want just because" from the OP.
As a composer yourself, I believe you won't appreciate any performer tells you that you wrote that bit "just because," right?
No, but I certainly get pointers (especially on other instruments) on how something could be written or notated better. In fact I do know that even Stravinsky would be altering his parts, after recommendations from performers.
This is one large reason why my scores lack pedal instructions and fingerings almost always (except in Sketch Music, where I didn't add them myself, btw): It's too personal and I find that I would be dictating things to the performer which may not work for them, as they do for me... My pedalling, my piano, my hands. Not theirs!
But just to be clear: I think that this particular prelude works like this very fine, since it gets out the melody with the right hand and works fine for people with large hands!
There's no reason to change it.