How do those games you listed actually qualify as new ideas?
CoD/BF/FarCry/Serious Sam... all sequels to niche but well established styles of FPS... which you rattled off along with the games. BL2 is the third or fourth attempt at first person loot grinding (calling these games ARPG is just depressing). Where are the new ideas there?
Better production and graphics don't equate to new ideas in my eyes.
My original point was that the child who originally posted suggests this game is somehow an "old school shooter". What does that even mean? Does it simply mean "just like the old one"? All of the old FPS games had extremely different feels and play-styles to them, so grouping together as some style to be replicated now seems odd.
If he meant, as you put it a "mindless shooter", then what is that? Mindless is a word justified only by your level of involvement, or commitment to achieving something at a high difficulty. There is nothing mindless about trying to beat something like SS3 on the highest difficulty levels, especially in co-op. Any of these games can be played in a mindless fashion, though your level of satisfaction may vary.