Outside of neutral meaning as "out of wedlock child", it can have a slightly positive meaning in context of "very impressive". It is always slightly derogatory but sometimes it carries a load of awe. Like, when the opponent in sports pulls out a truly impressive stunt gaining a lead against the odds, you might hear "that bastard" uttered with humor and respect.
One frequent phrase is "Magnificent bastard", a person who picks morally ambiguous, or outright immoral means to achieve their goals, but are exceptionally efficient and impressive at that, and not ashamed of it in the least, arising more awe than hate, often arrogant but still likable. Most impressive and likable supervillains (and quite a few morally ambiguous heroes) from fiction are often characterized that way.
There's also a strictly humorous positive use for this when a person uses subversive means to force someone for something good against their will. Say, you try to lose weight, but your willpower often wavers. If your partner steals all your sweets, you might say "you bastard", while essentially praising them for aiding you.
Nice catch.
My first thought was, why not? Reinvention can be a good thing, if you make incremental improvements (in the world of clichés, I believe that's called building a better mousetrap).
I wondered if maybe the idiom could be used positively or negatively, depending on the surrounding words. For example, I'd consider the expression:
Don't reinvent the wheel.
to be negative, as you describe. However, the phrase:
...continues to reinvent the wheel.
might have positive connotations, suggesting perpetual improvements. So, I looked for some examples. I did find this one:
The artist continually reinvents the wheel — constantly striving for a sublime composition of balance, harmony and refinement.
but the vast majority of the findings were indeed negative:
The idea behind design patterns is to not continually reinvent the wheel.
Moreover, lack of interchange with other teams also often leads researchers to continually reinvent the wheel.
Clients don't want to pay for suppliers to continually reinvent the wheel.
The more I thought about it, the more I wondered if the writer didn't mean to say:
Eminem has continued to reinvent himself, putting his life on display, through a bevy of syllable-heavy, metaphor-driven cuts.
Reinvention of the wheel seems to be a bad thing – a waste of time – but reinvention of self seems to be associated with quests to remain relevant, or on top of your game.
I don't know if I'd go so far as to call your cited usage incorrect, but I don't think an editor's call to maybe strive for a more apt metaphor would be out of order.
Best Answer
Ayn Rand wrote a book called The Virtue of Selfishness.
As an Objectivist, she espouses rational selfishness.
That page says
The connotations of selfishness outweigh its denotation. To express yourself without a lot of hand-waving, try qualifying it with rational selfishness, enlightened self-interest, or simply self-interest.