I've never seen Planet of Evil I don't think but if it is half as good as this one I just know I would enjoy it.
As for borrowing elements of stories, they do it all the time. They borrow from others and they borrow from themselves, it's hardly new so I wouldn't call it ripping off. The first season of Torchwood pretty much had every story rewritten from episodes of Buffy, Angel and X Files. It was so blatent, but still enjoyable.
Classic Who did it quite openly, especially in the 70s. Robot was King Kong, Brain of Morbius was Frankenstein, Talons of Weng Chieng was a Holmes pastiche etc. And they did all three of the Quatermass stories. Do I care? Not a nanite.
Yea I was going to say this. The Tom Baker years are the most obvious about it but it happened right through and isn't unusual in the newer stories either.
