I gave DADGAD a try for backing Irish tunes and didn't care for it. I find Drop-D gives you meatier chords and you can get the "modal" sound as well with a bit of finger stretching and the lower 3 strings still form the DAD so you can get those chordal runs down there. I discovered that the players whose styles appealed to me most, McGlynn, Brady, Doyle all used mostly Drop-D for accompaniment.
As for fingerstyle, it's a barrel of fun and you can do a lot with a minimal amount of left hand work (but you can do a tremendous amount with a lot of left hand work, witness Pierre Bensusan who adopted it as his primary tuning).