**** it, might as well compare Roy and Chrom:
Roy:
+ Extremely highly requested (Top 5 overall, him and Mewtwo are above every newcomer by a considerable margin in Japan). One of the few who's inclusion could be influenced by popularity.
+ Was in Super Smash Bros. Melee, so he has already appeared in a game.
+ Planned for Brawl, only cut due to time constraints.
+ Virtually guarantee if there are four Fire Emblem characters (which isn't likely, but still plausible).
+ Handpicked by Sakurai himself (Ike was the suggestion of IS).
+ Swords of Seals (which allows for use of multiple weapons such as healing) and emphasis on fire properties can help make Roy stand out.
- Low priority character; will not get in over Marth and Ike.
- Chrom will probably take priority if he is in.
- Competition from an Awakening rep.
Chrom:
+ If in, would take priority over Roy and possibly Ike.
+ Being able to change into different classes to utilize different weapons.
+ Recency isn't a determining factor, but it is enough to get Chrom noticed.
+ Fire Emblem: Awakening is an important title; it saved the franchise (although I doubt Chrom was the reason, but might as well put that out there).
+ Most wanted Fire Emblem newcomer (less than Roy, but still a positive).
+ Could feasibly get into a two slot Fire Emblem situation (although this only happens if Sakurai must cut Ike due to time constraints, not as an outright replacement)
- Not very unique without his class weapons/tag team duo.
- Faces competition from not only Roy, but also Lucina, so Chrom could still miss out even in a four slot situation.
- Sakurai may not see the need to include another Lord with Marth, Ike and Roy already available (and no, IS can't tell Sakurai what to do; they're not the Pokémon Company)
Both:
+ Well-received lord
+ Very highly received (although FE13 maybe less so in Japan)
- Could very well be a semi-clone (man, I wish we would get an unique Leaf with all of his Master Knight weapons, that'd be so frickin' awesome)