Why i Suck at Shooters

i have been playing a lot of games that i had previously downloaded on my original gamertag.  i decided that if i got a different console i would start up a new gamertag, because i had two consoles kind of fail on me (one sent in and replaced, that replacement was freezing frequently when i traded it in).  Anyway, i was playing Shadow Complex - and i re-realized something - i suck at shooters)

So why am i so bad at shooters?  Am i a lost cause? 

My biggest problem is with the reticule (the little aiming device).  i have a really hard time aiming with the reticule.  For some reason it takes me longer than average to put the cursor exactly where i want it (and it is always a struggle to put it where i want it).  It is worse in some games than others.  i did manage to beat the first three Halo games single player at the normal or above difficulty settings.  i guess that is one of the things that frustrates me with the current generation (and the abundance of shooters).  Aiming in games like Alan Wake is kind of a nightmare for me. 

i am kind of curious if it is the cursor move that is causing me problems or something else (like a brain processing delay).  i am kind of curious if a different input method (like Kinect) would make it easier for me to target enemies. 

i am not great at fixed shooters (stuff like Space Invaders, etc).  However, most of the older ones i play are more of a matter of patterns or "bullet hell" dodging.  Yes, i kind of like retro games (if my numerous posts on Game Room weren't evidence of that).