one way to avoid that particular issue would be to use infusions (either syrups or booze). Maggie Savarino's Seasonal Cocktail Companion is a great resource for getting started in that.
-- My bar just finally got around to doing a table tent cocktail menu (after updating the 5 year old folding menus).
Things I noticed:
Getting 8 new/unique cocktails is a lot of work and tinkering even for bartenders who know what they're doing, wouldn't wanna do it monthly.
It's important to have your bartenders enthusiastic about at least a couple of those things, otherwise they don't upsell it well.
Make them different, but intelligible. "Oh you wanted a manhattan with midshelf bourbon, why don't you try this thing that's like a manhattan, slightly fruity, and 3 oz of pure booze?"
Or make them very unusual: "Bitter citrus, honey, rosemary, and salt?" "Yup, it's a very savory cocktail!" "Well, why not."