I've been using bow ashigaru with significant success during my first several battles, and I've managed to beat some 5 and 6 star players doing something that I suppose they aren't used to.
Typically, I field my general, 3 katana samurai, 3 bow ashigaru, and one yari ashigaru. This varies on cost and experience of the particular units in use, usually plus or minus a light cavalry for quick strikes when I see the enemy botch their advance.
What I've been doing is using the +2 accuracy retainer, and setting all of my units up initially completely on top of each other. A huge wad of troops. I wait for the enemy to get ready, and then I select all of my units, let the clock tick down to 15 or 20 seconds or so, strike the gong, and sprint my units to the middle map high ground or some other critical location. Typically, the bonus buildings are secondary targets. Because I have control of the timing when I wait for them to get ready first, I universally beat them to the high ground, where I let my archers stop just before the peak of the hill, or perhaps the top of it. They fire at will until the samurai can run past and set up a position at the steepest point. The high ground is so significant that bow ashigaru can best the bow samurai with even mild increases, and since the enemy will likely move his units into firing range before he orders an attack, he'll suffer additional losses then, too. In every fight except for one so far, this has worked beautifully. In one of my three losses the enemy simply had swifter units, in another I was outflanked by hidden units and routed before I realized what had hit me, and in a third the guy was a 6 star with simply better troops.
But, in conclusion, using cheap archers to whittle down the enemy's experience units on the onset of battle seems viable, and I'm positive that it is why I have managed to peak at rank 930 last night, though now I'm sitting at 1300 something.