I hate the name as it is very hard to pronounce for non-english speakers...

And what's a Grotto anyway ? A cave ? (in french, the word "Grotte" means "Cavern")
 

yup, it's just a fancy way to say cavern (I think the only difference is that a Grotto can be man made). I doubt they were considering foreign pronuniciation when they made the name. And to be fair, I would be hard to come up with product names that weren't hard to pronounce in at least some foreign languages. Neverless, I'm surprised they haven't made foreign language editions of DDM like they did with Magic. I guess the market isn't big enough yet...