We must consider, since this is a new region, there need to be things... for one not every mon is... viable.
There will be the Pachirisu/Dedenne types, the Unowns, and things like that should work, but there's just a few flaws.
Now, the trick is, doing it well. Remember, if everything is gold, then gold will lose its value.
Enough about that, here's a feature: Ability Tutors.
Most pokemon gain access to one or two abilities to unlock for new playstyles.
In other things, here are a few ideas for new abilities.
Shaman Mask - For the first turn this Pokemon is in play, it cannot be damaged directly.
Availability: Shieldon, Bastiodon, Yamask, Cofagrius, Bergmite, Avalugg
Ambidextrous - User can hold 2 items. The item relegated as item 2 works at 50% efficiency.
Availability: Machop, Machoke, Machamp, Aipom, Ambipom
Punching Bag - User draws fighting moves towards it, and restores 25% health.
Availability: Makuhita, Hariyama, Amaura, Auroras
Brazen - This Pokemon gains +1SpAtk when it KOs something.
Availability: Azelf, Litleo, Pyroar
Pure Velocity - This Pokemon runs their damage calculations using its speed instead of Atk or SpAtk.
Availability: Voltorb, Electrode, Treecko, Grovyle, Sceptile, Accelgor
Specialist - User runs all attacks off of SpAtk
Availability: Abra, Kadabra, Alakazam, Mareep, Flaafy, Ampharos, Volcarona
Wishmaker - User begins a wish when switched in.
Availability: Wailmer, Wailord, Jirachi, Uxie, Tornadus
Sauna - This Pokemon heals 1/8th health from burns and doesn't get an attack drop. Prevents fire damage.
Availability: Paras, Parasect, Snover, Abomasnow
Brute Force - User runs all attacks off of Atk.
Availability: Machop, Machoke, Machamp, Rhyhorn, Rhydon, Rhyperior, Krabby, Kingler, Darmanitan
Stuntman - User switches in with a damage free substitute.
Available: MimeJr, MrMime, Shupette, Banette, All 4 Regis
Disbelief - Halves damage from fairy, magic, psychic, dragon and ghost, but increases steel, dark and normal by 50%
Availability: Pignite, Emboar, Zygarde
Blindness - Prevents vision based moves and abilities from effecting the user.
Availability: Zubat, Golbat, Crobat
Crusader - Deals 33% more damage to dark, ghost, dragon and magic types. (Does not stack for dual types.)
Availability: Escavalier, Cobalion, Terakion, Verizion, Keldeo, Skiddo, Gogoat, Xerneas