I think that Pyra and Mythra are actually a surprisingly good example of how "echoes" could be handled in future installments.
Unlike characters like Dark Pit, Lucina and Daisy, who are essentially carbon copies with different models and the occasional different animation, or even more popular echoes like Chrom and Dark Samus (EVEN THOUGH IT HAS ITS OWN PROBLEMS), the pair actually work pretty well because of how they're used.
Notably, I think that having them have the same basic toolkit works well - but an aspect I especially like is how they differ in damage output, lag, knockback and other such matters, whilst maintaining the same baseline animations. It's, to me at least, a clever way of handling the echo formula - and a great way to further differentiate the fighters without having to expend too many resources. Then, having different specials on top of that essentially differentiates them enough to the point where they feel different enough to be their "own characters," despite needing nowhere near as much work as other, more "unique" fighters.
For example, let's look at Lucina. As opposed to having her play essentially identically to Marth (aside from the tipper mechanic, of course,) what if her attacks were slightly slower, but dealt a bit more damage despite having similar knockback? It would at least make her a different beast - more equivalent perhaps to Roy, but with her own benefits and drawbacks. (For clarification, I haven't actually played Awakening, so this could genuinely be a bad suggestion in my part - it was just the idea that came to me given her playstyle and what I do know about her.)
Unlike characters like Dark Pit, Lucina and Daisy, who are essentially carbon copies with different models and the occasional different animation, or even more popular echoes like Chrom and Dark Samus (EVEN THOUGH IT HAS ITS OWN PROBLEMS), the pair actually work pretty well because of how they're used.
Notably, I think that having them have the same basic toolkit works well - but an aspect I especially like is how they differ in damage output, lag, knockback and other such matters, whilst maintaining the same baseline animations. It's, to me at least, a clever way of handling the echo formula - and a great way to further differentiate the fighters without having to expend too many resources. Then, having different specials on top of that essentially differentiates them enough to the point where they feel different enough to be their "own characters," despite needing nowhere near as much work as other, more "unique" fighters.
For example, let's look at Lucina. As opposed to having her play essentially identically to Marth (aside from the tipper mechanic, of course,) what if her attacks were slightly slower, but dealt a bit more damage despite having similar knockback? It would at least make her a different beast - more equivalent perhaps to Roy, but with her own benefits and drawbacks. (For clarification, I haven't actually played Awakening, so this could genuinely be a bad suggestion in my part - it was just the idea that came to me given her playstyle and what I do know about her.)