I do most of my swamp runs without any shield; Atgeir, Bow, and Stagbreaker cover all the bases once you learn how to use them. The key with two-handers is movement, don't engage mano-a-mano at short range, backup and time your attacks to hit as they come within range. Against archers, don't move in straight lines, they have horrible aim if you strafe a bit and use cover.