The only problem with the Grenade Launcher is the lack of ammunition, long reload times, and the risk of friendly fire. If a teammate at range is surrounded, and incapped, you can't fire at him, and the pistol accuracy is **** when running, so that's gone. It's good to have one teammate with the launcher, but using his pistols as his main weapon.
Zeth_Durron, all that you have said is correct. I was basing my comments on the single player game while at the same time using the great trainer from C.H. Under this scenario; there is no re-loading, no shortage of ammo and no damage to your A.I. co-players (however they do express irritation when the grenade blast hits them - which for me is often very amusing). But as you correctly point out, without using the trainer, the grenade launcher has drawbacks and short-comings.
They all have advantages and disadvantages.. though here is my favorite setup...
Combat Shotgun (only for witch kills and specials) Desert Eagle (for those that need an explanation as to why this is chosen over a melee weapon - smack yourself for me, hard - thanks)
Here is my 2nd setup...
AK-47 (preferably with laser sight, for specials and tank damage only) Desert Eagle (refer to first explanation)
Hence: 90-95% of kills are Desert Eagle for common infected, and the other 5-10% is for special and tank/witch kills with my 'main' (and I use that term lightly) weapon.
The only time I switch from my Desert Eagle to my 'main' is for specials, like a jockey or smoker etc, or witch or tank. And that is always either a combat shotgun or AK-47.
My thoughts on other weapons...
The SCAR? - less useful than an M16 because of the slight delay between bursts (I go for the head and only play expert realism btw so aiming my shots rather than waiting the time between bursts allows me to quickly change targets without any delay and pop another zombie head)
The AK is king number 1, even without a sight.
Both shotguns are useful, I prefer the combat, not that the spread difference between the two are enough to have any effect. If I switched to it, it was for a witch or raging masses of horde up close anyway, so aiming becomes secondary.
All 1st tier weapons (the silenced and non-silenced machine guns and shotguns) kinda suck. I prefer a shotgun (chrome) over the rest, but it dosent really matter.
And ok, here you have it... the reason melee weapons (ALL of them with the exception of the chainsaw in most cases) are almost useless... It is because of hit detection, invisible barriers, ping issues or any other number of problems encountered while risking a 20+ point drop in life that is almost guaranteed when any of those problems present themselves. Which, lets be honest, is quite often. Compared to almost any melee weapon, the Desert Eagle allows you to kill more effectively, and, more to the point, more safely. If you are horded, knockback/shoot/knockback/shoot/knowckback/shoot/knockback/reload/knockback/shoot and repeat.
It boils my blood when I see someone dropping their Desert Eagle for a Katana for the 'cool factor' lol! I guess they pay by draining our health kits, and then eventually watching us finish the level as a ghost! Unless of course they were lucky enough to rid us of our defib too... then they could come along.
I think that the AK-47 has the slowest rate of fire, but is very powerful. M16 has the fastest rate of fire, but has the slowest damage. The scar-h is the most accurate gun and is not too strong, yet not too weak.