Imo, archers were beyond great in RD. Taking my 20/20 Shinon as example who is not the best one, he was able to hit 4x thanks to doublebow, he would kill practically anyone with his 2 first hits, he would deal big damage to bosses, add the add the fact that he had good critical and the deadeye skill. Although his defense wasn´t the best, his evasion was high so he always had a big advantage against heavy units and mages.
But the whole game is unbalanced. You start with pretty crappy units, that are really fragile. Luckily some quite useful units join later on. On chapter 2 many units are great and really worthwhile and in chapter 3 most units are very powerful. It ends up in a very unbalanced party, with very weak units that you hadn´t the chance to use much in order to keep them alive and very powerful ones that were already powerful in their respective chapter. Add to that all the abundant extra skills you could give them (non-existent in the other FEs) and all the powerful weapons you could find (only a limited amount of them are available in the other FEs) you ended up with overpowered units, even though their stats are capped. All chapter 4 was a breeze for me, only Drag. K. and final boss posed some threat.