I've only seen a couple viburnum in bonsai shows at CBG, and they were not very good. The tree looked more like a shrub in a pot than a ''tree''. Attractive enough, but definitely not one of the better species. I'd pass on it for bonsai.
If you had a picture of the flowers, you should lead with that for getting an identification. Flower structure is key diagnostic for botanical identity.
There are hundreds of viburnum species, and a fair number native to North America, they are an interesting group of flowering shrubs. Most have attractive flowers and fruit, many have edible fruit. Using the flower photos you should track down which species you have and decide then whether you want to rejuvenate the bush, by what technique or whether you want to remove it.