Non-Legendary Tier List (beta)
Besides legendary species, regional species and those that are only viable with legacy moves are excluded.
Tier 1
Machamp (Counter + Dynamic Punch): Most crucial gym attacker due to dominance of Normal-types, with Lapras and Steelix also common; Main counter in Tyranitar, Absol and Regi-trio raids.
Dragonite (Dragon Tail + Outrage): Top generalist gym attacker, good gym defender, counter to many Dragon-type legendaries; Hurricane is useful for Machamp solos.
Blissey (Zen Headbutt + Dazzling Gleam): Best gym defender and main coin source.
Tyranitar (Bite + Crunch): Crucial to Alakazam, Gengar and Jynx solo teams, top counter to many Psychic-type legendaries including Mewtwo; Stone Edge is useful against some legendaries.
Tier 1.5
Gardevoir (Confusion + Dazzling Gleam): Great for Machamp solo teams, fantastic gym defender, counter to many Dragon-type legendaries and gym defenders.
Gyarados (Waterfall + Hydro Pump): Good generalist gym attacker, good gym defender, counter to some Tier 4 raids and future legendaries.
Hariyama (Counter + Dynamic Punch): Similar roles to Machamp, with lower DPS but higher TDO.
Tier 2
Alakazam (Confusion + Future Sight): Crucial to Machamp and Gengar solo teams; Psycho Cut is good for dodging.
Espeon (Confusion + Future Sight): Crucial to Machamp and Gengar solo teams; easy to acquire.
Flareon (Fire Spin + Overheat): Great for Jynx solo teams, relevant gym attacker; easy to acquire.
Salamence (Dragon Tail + Draco Meteor): Slightly worse Dragonite.
Tier 2.5
Gengar (Hex + Shadow Ball): Crucial for Alakazam and Gengar solo teams. Even more powerful with legacy move Shadow Claw.
Exeggutor (Bullet Seed + Solar Beam): Relevant gym attacker, crucial for Omastar solo teams, can contribute to Machamp solo teams with Extrasensory + Psychic; easy to acquire and even stronger with legacy move Confusion.
Snorlax (Zen Headbutt + Heavy Slam): Great gym defender, will earn many coins; niche attacker.
Chansey (Zen Headbutt + Dazzling Gleam): Great gym defender, will earn many coins.
Tier 3
Golem (Rock Throw + Stone Edge): Niche gym attacker, counter to some Flying-type legendaries.
Jolteon (Thunder Shock + Thunderbolt): Relevant gym attacker; easy to acquire.
Metagross (Bullet Punch + Flash Cannon): Relevant gym attacker, great for Jynx solo teams, can contribute to Machamp and Gengar solo teams with Zen Headbutt + Psychic.
Vaporeon (Water Gun + Hydro Pump): Slightly worse Gyarados; easy to acquire.
Tier 3.5
Rhydon (Mud Slap + Earthquake): Niche gym attacker, counter to some Electric-type legendaries, Regirock and Registeel; has great evolution in Gen IV.
Scizor (Fury Cutter + X-Scissor): Niche gym attacker, counter to many Psychic-type legendaries.
Houndoom (Snarl + Foul Play): Can contribute to Alakazam, Gengar and Jynx solo teams.
Jynx (Frost Breath + Avalanche): Niche gym attacker, counter to many Dragon-type legendaries; faces stiff competition from Lapras/Walrein and will be eclipsed by Mamoswine in Gen IV.
Answers
I am certainly open to dropping Snorlax and Chansey to level 3 while bringing Golem (what are its "many uses in current meta"?) up to level 2.5. How important defence is really depends on where you live; new players in Singapore, Hong Kong, Tokyo, etc. should acquire a decent Blissey (plus a few other top defenders) as soon as possible.
I don’t believe Psychics are that relevant, only time I ever see Alakazam or Espeon is for Machamp raids, and we got enough champ already from previous two events.
Golem is way too underrated, deserves at least tier 2
If you are excluding Frenzy plant, leaf blade Sceptile is better for grass offense
The only suggestions I can think to make here are to swap tier positions for Golem and Flareon (as Golem is often more relevant than Flareon), and reconsider the "good gym defender" statement on Gyarados. It has high CP, but just about any Mon with double electric moves will bring it down incredibly fast. Just my 2¢
I think Guardevoir is way overrated...I actually never use both of mine. I just use my Dragonites. Golem certainly deserves higher and I would also argue Rhydon needs to be higher. Flareon? I never use mine. Alakazam and Espeon only have use for Machamp. They are essential here for new players especially but other than that they have no use. If hariyama is only half a tear below machamp, why is salamence one whole tier below dragonite?