For what it is worth, Weyermann now sells a Vienna Barke malt that is very flavorful. I try to avoid any crystals in most every lager style, but a light hand is permissible. Actually, the BJCP Style Guideline for 2015 (Comments and Style Comparison sections) capture the essence of the style:
"Comments
A standard-strength everyday beer, not a beer brewed for festivals. American versions can be a bit stronger, drier and more bitter, while modern European versions tend to be sweeter. Many Mexican amber and dark lagers used to be more authentic, but unfortunately are now more like sweet, adjunct-laden Amber/Dark International Lagers. Regrettably, many modern examples use adjuncts which lessen the rich malt complexity characteristic of the best examples of this style. This style is on the watch list to move to the Historical category in future guidelines; that would allow the classic style to be described while moving the sweeter modern versions to the International Amber or Dark Lager styles.
History
Developed by Anton Dreher in Vienna in 1841, became popular in the mid-late 1800s. Now nearly extinct in its area of origin, the style continues in Mexico where it was brought by Santiago Graf and other Austrian immigrant brewers in the late 1800s. Authentic examples are increasingly hard to find (except perhaps in the craft beer industry) as formerly good examples become sweeter and use more adjuncts.
Characteristic Ingredients
Vienna malt provides a lightly toasty and complex, Maillard-rich malt profile. As with Märzens, only the finest quality malt should be used, along with Continental hops (preferably Saazer types or Styrians). Can use some caramel malts and/or darker malts to add color and sweetness, but caramel malts shouldn’t add significant aroma and flavor and dark malts shouldn’t provide any roasted character.
Style Comparison
Lighter malt character, slightly less body, and slightly more bitter in the balance than a Märzen, yet with many of the same malt-derived flavors. The malt character is similar to a Märzen, but less intense and more balanced. Lower in alcohol than Märzen or Festbier. Less rich, less malty and less hop-centered compared to Czech Amber Lager.
Vital Statistics
IBU
18 - 30
SRM
9 - 15
OG
1.048 - 1.055
FG
1.010 - 1.014
ABV
4.7% - 5.5%
Commercial Examples
Cuauhtémoc Noche Buena, Chuckanut Vienna Lager, Devils Backbone Vienna Lager, Figueroa Mountain Danish-style Red Lager, Heavy Seas Cutlass Amber Lager, Schell’s Firebrick."
I must say IMHO that the Devil's Backbone version is pretty well made and quite drinkable.