[Baalz]

I don't think there's any reason that Atlantis is relegated to a defensive role, though they have some serious home field advantages. Everyone has their own preferences for scales, but I think death has a very good synergy here. Because your troops and mages (other than one) are so cheap, you're a bit less desperate for gold every turn. Your reliance on cheap sacred units and mages means your upkeep will be very low, helping offset the decline from your death scales. You can fuel a very respectable expansion with dual blessed Arssartut, there's no reason you shouldn't be able to field a force every other turn capable of chewing through most indies with very few casualties using archer screens - that twist fate helps a whole lot at this stage. Additionally, with the ease of expanding into the water there's a lot of options on the table.

As to your question about massed archers, you've got several good options. Your shielded Ice Guards are very good against archers even in neutral scales (you'll have to be careful in heat scales). Mournful also do pretty well with a shield, 15 armor and good hitpoints. Clever archer screens make it hard to target the Arssartut as they're not large and twist fate will help a lot vs the stray arrow or two. Finally, if the archers are massed to such a point you don't think screens will be effective just fall back on the fact that you're a nation of heavy infantry....pull your Arssartut out of the fight and let your shielded heavy guys ignore the arrows - they're certainly fairly tough on their own strenghts, and if necessary they can be superb blockers while your mages do the killing.