well...MD does get a 'bit' boring after the storyline cuz you'll be just going to dungeons and rescuing...BUT!! that's not the only thing you can do, cuz you can also set a goal of recuiting all the pokemon in MD (which can be hard and challenging) and go to special dungeons like Purity Forest, which can be annoying and fun at the same time since you have to start at lvl. 1 w/o any items and it has 99/F. lol.
Overall, I think the gameplay is really cool and different in MD cuz there are many different items to use like the 'Gummies': raising pokemon IQs so they have more 'options' if they are your partner, 'sticks + rock's where you can 'throw' them besides attacking a pokemon, there are traps which can affect how you do, like 'sticky' trap makes ur items useless and you can't use them. and other many cool items to have that you can't get in the RPGs.
also there are more stragety play in MD than RPGs too. especially if your partner is a new recuit and is really lower lvl then you then you have to make sure they don't faint as well....or you'll lose them and have to recuit them again.
plus if you are defeated, you can also call for help WORLDWIDE using passwords to this site:
http://dungeon.filb.de and the waiting doesn't take long. which the rpgs cannot do. ^^
so yea...MD is really cool! that's why I got it in the first place and I'm happy with it since it's quite different than the RPGs (besides RPGs can be quite as boring as well since it's just lvling up too + making pokemon stronger....~ xD ) So, it's a nice break avoiding playing RPGs all the time. ^____^