Rephaelite costs more than two Palankashas, but doesnt have as much offense as two Palankashas (or staying power, for that matter). Also, their summons are inferior to Lanka's (with the exception of Gregori), and their mages arent as good for research and crafting equipment.
I'm really qurious where are strengths of EA Arco btw.
Sure, research is there. But their troops are simply bad, and mages, while nice in their own way, have no endgame paths (weak astral, no death, no blood). And no national summons... Of all things, ancient Greece has no summons - its just not fair in my opinion.