>>40064688>RoostIt would need to get MASSIVE boosts to its defenses in order to make Roost a viable option. Unless Sirfetch'd is getting something like a +150 BST when it evolves and loses some SpAtk to put into HP, this isn't going to see use outside of single player no-items no-pokecenters runs.
>AgilityMostly useless. Doubly so if it doesn't already get a good boost to its speed.
>Flying coverageIt's only okay. It covers Bug types and has good neutral coverage, but it doesn't have the same kind of coverage that moves like Knock Off (which it does admittedly learn) or moves like Thunder Punch, Ice Punch, and Stone Edge have. Using Stick at all means you're forgoing a Life Orb or Choice Band, and not even the regular Farfetch'd will always use Stick in favor of the reliable damage of Life Orb.
There are three potential outcomes for Sirfetch'd:
1. It gets a huge speed boost. If Mienshao isn't in the game, Sirfetch'd might have a niche.
2. It's just Farfetch'd but better and is maybe kinda fun for single player but that's about it.
3. It gets a Gigantamax form so it can have three turns of being useful and then is trapped in the Shadow Realm (Pokemon Home) for gens 9, 10, and 11.