Re reception of clones: it varies.
A bad clone will be seen as a ripoff and hated more than a bad original game; a good clone will be praised as a spiritual successor and improvement of whatever it's ripping off. Generally they'll be more forgettable than the original, regardless of quality level, so they fade to obscurity faster.
If this is what you want to deal with, I guess there's no stopping you.
Re patents:
For a more recent example, recently the Nemesis System was patented, so you're not allowed to have procedurally generated characters that evolve based on your interactions with them. (The patent probably is more specific than that, which would make it possible to make similar-but-different-enough things, but it's more about who can afford the best lawyers and not who's technically right). There was a patent that made it impossible for others to have minigames during loading times, which expired at about the point where games loaded too quickly to need the additional distraction.
If you want to rip stuff off, you should ideally pick mechanics that are so old and commonly used that they're generic (which means they're unpatentable, untrademarkable and uncopyrightable). Jumping, for instance, has been around since the dawn of bipedal creatures, and even if it was patented on the inception of the first platform game, it's expired now (and it can't be patented now, because it's public knowledge).
For a slightly less safe option, copy other mainstream indie games - if they got away with it, it's probably safe. Or games that are older than the effective time of a US patent.