Hmm.. Yeah I guess if you look at it that way, v happens to fall minor a lot. I look at modal roman numeral progression as still being in the context of a major or minor key. So if I write something in a Dorian mode, the modal center is still IImin instead of Imin. I guess it’s cause I was taught that modal songs are not diatonic, and “I” makes me think tonic. I’m sure you understand. It may seem confusing to many, but it’s actually very simple to work with especially in a major/minor dominated world.

As for the progression, yeah that is a very common one (extremely common). Even though, I would still be compelled to make the A a dominant chord. A string of minor chords contained in the 1, 4, 5 block to me is almost “lifeless” or “monotony”. A7 just seems to liven it up, but not take away from the minor tonality. Since the dominant chord is a bluesy sounding chord anyways. Of course there are times when you want to leave it be as Santana did, but it seems this one takes more consideration. A good point though.

I figured out one that is not too bad in the key of A minor. Am - Em - G7 - D Changing the Em to an E7 actually doesn’t need to be if I’m going to G dominant afterwards. It definitely sounds better to leave it an E minor chord instead. Also the D major chord at the end is a nice twist on things.