(I'm taking it to mean Ice cream sundae type dishes...)
OVER: It's a real toss up between wafers and mini marshmallows. I mean, both don't particularly add any new flavour dimension, heck I usually take the wafer out completely and just leave it on the side. Mini marshmallows are visually delightful yet lack any real taste appeal, its all texture and show really. Yet BOTH are common features on a sundae with 'the works' I find, and it's like...Great, you've made it look pretty, but replace that wafer for a waffle wafer, or crumble up a graham cracker and sprinkle it over and NOW we're talking. And those mini mallows? How about you get some chocolate instead, and we'll all be much happier.
UNDER: Nuts. I genuinely love almond flakes/crumbled hazelnut pieces on my ice cream sundaes. I find they add a nice crunch element to the dessert and blend well with both the ice cream and the chocolate sauce. I also really love it when they use nutty chocolate like Ferrero Rocher crumbled up in desserts like these. (To be fair, I love it when they use just about any chocolate bars/sweets (like m&ms) in these desserts but seen as this seems to be used more and more its hardly underrated now!). But most people think nuts don't add anything, or dislike the addition, whereas I think if they give it a proper go they'll find just how good they are!
OVER AND UNDER OF WAFFLE DESSERTS?