Mudlady, from experience I did at a former residence and from visiting garden nurseries with raised beds exhibited, they usually consist of railroad ties, one in, one out...so let's assume 6" to 8" makes for a nice looking bed.

You are right though about possible increased dryness....especially if the bed is in line to be buffeted by drying winds. The raised soil can invite windy conditions to affect that more than a regular bed.
But, drainage, where looked after, is much the preferred way.

Your leaving bulbs in the ground does bring up the question...what kind of bulbs do you in your zone 5 allow winter to sit on top of. Surely, not dahlia, or glads, they HAVE to come up otherwise they'll be squirrel fodder in the spring.

I have 195 bulbs from Brent and Becky's that I believed I was going to get in this fall. I kept waiting for the contractor who did the digging and cemet stuff when the house was built 16 months ago. He kept saying he was going to come back to install some drains and adjust the grade around the house. He says he never made it here because of the rainy fall. Now I have to do something with mostly daffodils, some tulips, and a few crocus and grape hyacinth bulbs. I thought I could plant them in the better drained spots of my land but as we put in trees and bushes I noted how very damp the soil was even in the "good" areas. This was good farmland until I bought it and I know it can sustain crops and grass. I also have half a truckload of topsoil on hand. I have to do something to save the great bulbs that are sitting on my kitchen counter. (My thermostat is kept at 60 degrees.) I would prefer to keep them in the garage but I have a terrible mice problem and don't know if they would chew the bulbs. Maybe I should leave the bulbs in my car? Anyway, I have a friend who can do or fix anything and he will build me a long rectangle on my side of the ditch, out by the road. My plan is to make a large bulb garden and after blooming I will put annuals around and inside the planter--taking care to let the bulb foliage die naturally. If the planter protrudes 12 inches above the grade, and the soil I fill with is amended for good bulb growth, will this work?
Mudlady

Grape Hyacinth won't mind the wet, maybe the daffs too. The really vigorous old hybrid daffodils thrive on rich and even heavy soils. Dutch Crocus prefer good drainage, many species crocus and tulips absolutely need good drainage. A foot deep if fine, but don't go amending too much. Amend with gravel if you already have good soil. Consider some chicken wire at the bottom of the planter and on top to prevent critters nibbling your bulbs.