I've really been rethinking crystal malts recently because I've found the opposite - throwing crystal in everything just because it's there and it complicates the grain bill a little. A lot of my stouts (not my recipes) have a high proportion of crystal malt in them and while it can make it dark, they have a place but shouldn't do the 'dark' work in a stout. They should compliment the recipe.
In might all be in my head but I find crystal to be a little bit more one-dimensional than we give it credit for. There's a lot of variety and subtle differences (i.e. EBC, country of origin) but at the end of the day they taste like crystal. This works well in recipes that that are suited for crystal, but muddies the waters on recipes that aren't.
I'm now moving away from crystals in general unless it's a bitter or stout. Some colour adjustment can be achieved by alternatives like midnight wheat, chocolate, roast barley, black malt or even candi syrup without much of a flavour impact (especially in ales). I've found Vienna and munich can add quite a lot of body and are a great alternative to crystal, but are used at higher proportions. A low portion of brown malt, biscuit, carafa I or some of Gladfields alternatives like Redback add quite a bit and in the right proportions change a beer entirely.
Obviously your mash schedule and base malt will have a lot to do with body. Increasing mash temp or moving from pilsner to ale, MO, pearl etc. will make a big impact. Also don't discount the effect yeast can have on a beer - try WLP008 for an alternative to WLP001 or Wyeast 1056.
As always though a mish-mash of different hops, yeast and malts won't necessarily make a better beer. I suggest using an ale base malt and adding one or two elements with a simple hop schedule to see the impact on each. In summary -
- Ale base
- Moderate proportion of munich or vienna OR addition of a darker alternative OR both
- Mash temp 66 - 68°C
- Lower attenuating ale yeast
- Don't over-complicate the recipe