Should vasodilatory therapies be considered first-line in the management of hypertension in patients with severe aortic regurgitation?  

Yes, ACEi or ARB or dihydropyridine Calcium channel blockers would be the preferred anti-hypertension medication classes in patients with HTN and significant aortic regurgitation. There is no role, however, for using these agents in patients with severe AR without HTN. 

I recommend ace. Inhibitors and ARB at first but not CCB and may precipitate syncope.