I personally hate these guys (no "feces" I'm playing Minecraft). In the wild and outside the wild. I wouldn't mind them if there was actually a fair chance to fight them... When I see "A wild Creeper has appeared". I cry. Q___Q____. <--- See the rivers of my tears.
The thing I'm suggesting is take Creepers from the random encounter plug in. Or if possible change their explosion timer so they can start setting off till like 1-2 seconds after spawning (I was thinking 1.5 would be the perfect timer). Just so you have a chance to actually fight the guy before he explodes.
Now I already know the first thing I'm going to see is "Well just wear blast protection armor, and you should be fine". However that's not the problem actually. I rarely die to creepers. I protect myself just fine. I would just much rather have a chance to fight them, get the exp, gold, and possible sulfur (for what it's worth). Just the chance too, other then it spawning and instantly explodes.
So yeah it's a suggestion. I bet it's been suggestion before, and you probably have a good reason for the creepers to be there, or you guys just like laughing at the people that come up "Bob is blasting off again... *ding*" I find it entertaining, especially when I died from a creeper for the first time (cause I'm James... From Team Rocket.. hah?... OK bad joke).
P.S. DUDE? WHERE ARE THE SPIDERS? ADD THEM TO RANDOM ENCOUNTER ALREADY!?