Do you want it to taste "good" or sickeningly sweet? Seems like the latter if you're dumping syrups and artificial flavors into it.
Boring does not necessarily mean "bad".
I personally prefer brewing (cone/drip or french press) with green cardamom pods added to grounds prior to brewing. It adds a pleasant, mild-spicy quality like ginger without the 'heat'. You can also work with star anise or cloves in a similar way, just use less spice than you would with cardamom. Another alternative is to brew chai and use that instead of water to make your coffee. However, I only recommend this with a french press, not a drip machine.
You can also try NON-chemical sweeteners like agave nectar, honey, or stevia.
The point of veganism aside from the emotional stuff is to get back to a more wholesome, unprocessed form of life. That's why raw diets are so popular and effective with vegans. Freaky syrups, artificial sweeteners, and overprocessed condiments are missing the point. You should probably reconsider veganism if that's your preference.