Tropes are writing conventions that you see over and over, so much that they become a classic. I was taking a look at this website and decided to search for TGL and found a page for it:
http://tvtropes.org/pmwiki/pmwiki.php/VideoGame/TheGuardianLegend
(WARNING: Tv Tropes is known for stealing all of your free time)
it's nearly impossible to come up with anything original nowadays
Besides, who cares about the plot/features, so long the gameplay is what counts
Tropes reapeat themselves because they work (mostly).
There's nothing detractive from that.