Sounds like you may have skipped the step of letting the dough rise before putting it in the fridge. We manufacture Liege waffle dough wholesale and we find that you don't even need to let it rise that much before cooking. If you make the dough, add butter, add pearls, let it rise, then you can actually cook it right away. You don't have to retard the fermentation overnight and you'll still get a very good waffle.
Or, maybe you didn't use bread flour that is high in protein/gluten. If you use cake flour, you'll get a very different result.
Or, a step that is often missed is stretching the dough into a semi-flat oval before pressing with the waffle iron. By stretching the dough, you give it enough space to expand inside the waffle iron. By doing this, you end up with a lighter less dense and doughy waffle. The inside texture/density of the waffle should be somewhat similar to challah bread. Give it a try.
Lastly, maybe your temp is too high so you didn't cook the dough enough leaving it very doughy. You really need to be in the 350-360 range for about 2 1/2 minutes.