Obviously the game will not do it for itself, because the restrictions are there to make the races what they are, the classes what they are, the game what it is. So if someone was looking for "official" (as stupid as they definition is) changes to open choices up, they'll be waiting for a long, long time.
Now for everybody else... any table can go ahead and mix and match abilities till the day is long. So long as the DM and the players have relatively good ideas about the power of the various game features as played at their table, there's no reason not to fiddle and futz with them. I mean, I'm a HUGE proponent of "class feature swaps", rather than level dip multiclassing (which players do just so can get that one single ability that is normally only acquired from a different class.)
There is definitely truth the idea that any game played long enough will lose its freshness and originality. If you've played every class several times over, the idea of wanting to create "something new" using the game's mechanics is not out of the realm of possibility. But I know for me, that usually means one of two things:
1) I'm better off playing a whole different game system (even if I wanted to remain in the fantasy theme) just so that I have new and fresh ways to interact with different rules and dice and help change/reset expectations.
or
2) Push the mechanical focus far back as possible and really just concern myself with character. Personality, needs, wants, attitudes, loves, hates, etc. Because by doing that... my concern is purely for what my character is and does through narration, and I no longer care about whether there is a game mechanic to "back it up". To bring it back to the other thread where I was talking about this stuff... if I want to say my PC was the "Greatest Swordsman In The Land"... I can just do that in the narration and his representation in the world, and not need my mechanics to emphasize it. Yeah, the mechanics are still there to play the combat mini-game when it comes up as necessary... but that mini-game is no longer the focus and end-all-be-all of what playing the game is. Instead, the improv is the end-all-be-all, and the mechanics are just an extra byproduct to enjoy when it comes up, but not care in the slightest how "precise" or "exacting" it is.
Obviously most people have the most difficult time with #2 (almost nobody seems to like sidelining game mechanics in their thoughts and minds as much as I do), so in that regard playing a completely new game like #1 is a good alternative way to go.