I honestly think Explosives have it worse than Energy Weapons. Until you're at high levels, there's simply no great explosive weapons. Then you get Mercy (I don't want to spoil what this is before you get it, but it's amazingly funny) once you can beat the Legendary Deathclaw, and you get a Fat Man. But other than that, they all have their use, but I see no reason to use them most of the time. They're more of a secondary weapon than a main weapon or a weapon just for messing around.
C4s have a nice, practical use, but they're rare and expensive.
Not to mention if you're on Hardcore mode Explosives weigh too much to carry around for any long period of time.