My opinion on the current meta for merc strengths in competitive (casual to I guess).
S- Sawbonez
A- Fragger, Vassili, Bushwhacker, Nader
B- (Aimee), Phoenix, Arty, Thunder, Redeye, (Stoker)
C- Sparks, Fletcher, Kira
D- Aura, Proxy
E- Skyhammer, Phantom, Rhino
Sawbonez- He is top tier, and by far the best merc in the game he is a must have on any team at the moment.
Fragger- He has high health and high damage, and his nade is one of the best abilities in the game. On top of that he has access to great primary weapons.
Vassili- The top sniper in the game, his heart beat sensor is another one of the strongest abilities by giving himself and his team sight on the enemies. As well as having the MOA this is currently the best sniper in the game and if you have someone who can snipe decently then he will be essential to the team.
Bushwhacker- The best engineer in the game. Some argue that fletch is a better choice, but Bushwhacker is overall a better merc. His turret is great for defensive plays as well as having the Kek available as his primary.
(I am not a fan of shotguns so this one is kind of up to you)
Nader- Her ability allows for great area control and can lock people down or clear an objective will relative ease. Her martyrdom is an added bonus and can clear an objective if the enemies decide not to gib you. Not to mention she has the crotzni in her arsenal.
Aimee- could be tier A but at the moment people don’t use here Snitch at an optimal level. If used correctly and in tandem with a good team could create total destruction. Due to the fact that enemies will not regen health for 7sec or until healed on top of the fact they are taking 25% more bullet dmg.
Phoenix- To me he is one of the most balanced characters in the game, he has a decent burst heal as well as his personal revive, but more often than not he will be gibbed before he can use it. He has access to great primaries and a decent level of survivability, but he ultimately falls short of Sawbonez
Arty- One of my personal favorites to play but not a top tier character in the current meta. While he is not high on the list he is in my opinion the best merc with the ability to easily destroy an EV plus his ability can also be used for area control. With access to the Br-16 he can be a very strong merc in the hands of the right player.
Thunder- He could go up or down on the list (most people would probably say he belongs in C or D tier) but if you look at what his ability can do, he has the potential to cause an enemy team wipe during a team fight or push if used correctly.
Redeye- Falls in the same boat as Aimee in my opinion, but her ability is more useful in my opinion. Also, he has to worst primaries of the 3 snipers thus his placement in the current tier list.
Stoker- His ability is great for area control but due to its heftier cooldown time it is weaker than a Nade or Grenade Launcher. He is a fun character and could see him being played, but as he is now there are better mercs to pick.
Sparks- Her ability is great if used efficiently; pair that with her Companion Agent loadout and someone who is decent with hitting headshots and she will become an extremely deadly combatant. Also, being able to revive from a distance can be extremely helpful to the team, but her low health pool makes her very easy to kill for someone with decent aim. (personally one of the most fun characters in the game in the game, so it is sad to see her this low on the list, but like I have said this is my opinion and at the hands of a pro she could probably be a higher tier merc).
Fletcher- Again there are people who would argue he is a better engi than Bushwhack but in my opinion he relies too heavily on his abilities to confirm kills or do anything for the most part. On top of that his weapon pool is not amazing and he is mediocre for team comps.
Kira- Another character who could be higher on the list but her health is on the low end which means she is less likely to survive in a team fight. Her ability is good and can destroy a team if you are not paying attention but competitive teams will be doing just that.
Aura- in my opinion the weakest healer in the game (but I can see many people disagree with me on this one) her heal station is great… but it can be destroyed and it limits her from being an aggressive healer. Also her low health pool doesn’t help. (in casual though she is pretty damn fun).
Proxy- Easily the weakest engineer in competitive in my opinion her mines are easy to detect if you are listening. She has a lower health pool than the other engineers. Unless you have a really good proxy player she is the worst of the engineers.
Skyhammer, Phantom, Rhino- The weakest mercs in the game at the moment you will usually only see people playing them if they are new players or on free rotation. Phantom is better than skyhammer and Rhino in my opinion but is still one of the weakest characters in the game especially when it comes to team play (note: his newer ability to disable deployables is very useful which could bring him up one tier, but I still think he belongs where he is at).
) and Stoker as ammo support until the recent changes to his molotov. So something that gets picked as a frequent on BOTH teams EVERY PUG should be an S tier in my opinion. And also? Any Arty main will probably bring Arty over Stoker, and Arty can be used very competitively. Arties can kill the EV every 49 seconds. Skyhammers take 90 seconds for cooldown. So if the enemy happens to constantly be healing that EV, Two Arties with good communication are always better than Two Skyhammers time-wise. It only takes 3 arty strikes to kill an EV unless you’re a bad Arty. (My point is that you have Arty in the wrong category OP, and Skyhammer does not belong in the NoobE category at all.) Also, Phantom has some utility in competitive play, but mainly only great communicating teams will use him to counter Bushwhackers and Auras. (See Leb from D.92 here in case you’re wondering.) Also, Redeye is the best Recon, you need to move that appropriately…