nade launcher looks fine.
no need of new weapon, just some way you could trow your nade much further that now would be fine...
maybe all we need is this: when you select your nade, the aim-pointer (don't know the term in english, sry) changes, the guy keeps a position like in americas-army:
http://www.americasarmy.com/gallery/screens/sfdockside5_800.jpgor like here:
http://www.americasarmy.com/gallery/screens/sf_wtreat6_800.jpgthen all we need is timing:
1-mouse-key-1 -> normal launch: 5 secs and nade blows up
2-mouse-key-2 -> alt-launch: keep pressed and timer starts, release and trows nade.
that way you can prevent aliens escaping from nades.
also, launching could work like americas amy launch:
1-activate nade (you may insert a 1-sec delay), but timing does not starts. you can keep pressed mouse-key-1 'till you want, nade will blow just 5 sec AFTER LAUNCHED.
2-activate-nade (1 sec delay), timing starts. keep it too much and you blow up
--edit:
this could translate into biles blowing after 5-10 sec with mouse1-press or blowing immediately with mouse2-press
--edit2:
we also need more visible nades -.-
those 2-pixels, bouncing (why the hell do nades bounce?

) things are almost invisible -.-