I personally think grenades are as important to the core gameplay of Halo as the shooting, so I don't think wishing for a seperate playlist just without grenades is as legitimate as, say, wishing for one without armor abilites. If you purely want shooting, the closest thing is SWAT, in which "marksman skills" matter even more there because you have no shield.
Also, I don't think it's that bad with the grenade spamming and I don't have the impression that the "bigger explosion"-perk gives you that much additional damage (although it would be nice for someone to test that out). But I agree that you shouldn't be able to carry more than 2 grenades.
I also agree with the Plasma grenades - what the hell were they thinking? It's not that bad in Team Slayer, but in Big Team Battle? I use them myself all the time, but they make the game really imbalanced. Especially when you're able to spawn with a Plasma Pistol in addition to that. The Vehicles are already quite a bit weaker than in previous games and with my PP+Grenade Combo I'm able to destory every Warthog/ Ghost etc. that crosses my path, where in previous games I had to run away or get the Power Weapons. Spartan Laser, Bazooka etc. aren't even necessary anymore.
Where is the classic playlist we were promised before launch??