My case for Agent Venom being buffed before Antman (and other champs)
Antman:
18-63% Glancing chance (reduces damage to 50% and ability accuracy 100%)
Light attacks have 20% chance to fatigue the opponent
Sp2 turns fatigues into poison
then come the notable synergies:
Yellow Jacket gives 6% attack, who also has that synergy, so +12% attack total
Doc Ock makes Antman reflect 40% damage when glancing
Psychoman lets Antman place two staggers on his sp1
Ghost gives 15% attack for each debuff on the opponent, which is sick, not to mention +15% attack per buff on Ghost
Wasp gives increased armor rating and gives Antman 25% attack increase for 10 seconds after glancng
Nick Fury gives 3 evade charges, the same synergy he has with Quake
and other, less important synergies for Antman
Agent Venom:
Klyntar rage gives increased 9-24% increased attack until he gets hit 5 times, and small crit damage buff
70% chance to purify debuffs
50% reduced evade chance
Special attacks can inflict a small bleed
Sp2 inflicts an incinerate
then come the notable synergies:
A number of symbiotes give 6% health, and he does, so 12% total
Spidey gives 4% health and attack
Goldpool gives 20% increased bleed damage
Sym Supreme gives 20% increased bleed duration
and other, even less important synergies
Antman may have few abilities, but he can actually be a decent champ with synergies, which you will invariably be bringing him for. Lots of people already quest with him for Ghost or NF evade charges, but I don't think I've ever seen anyone put Agent Venom on a team or even suggest using him for any content. His synergies are either practically useless, or could be obtained with other better champs. The two main abilities that Agent Venom has are his debuff purify and reduced evade chance. The problem with these two abilities is that in endgame content, the 30% of debuffs that get through can kill you pretty easily and one single missed evade can KO you in most situations, so you are never really gonna pick him when you expect to get damaging debuffs or when an opponent has any sort of evade chance. There are other champs with much better purifies and evade countering, which is usually a small part of their utility, not 60% of it. I'm not saying that I don't think Antman could use a buff, but he will get one regardless. I'm saying that he has more value in the game as it stands than Agent Venom, which is what should objectively determine who gets the more immediate buff.
As a side note, here are summaries of the other champs:
Jane Foster (Thor), who I think deserves the buff after AV:
Guaranteed crits and increased crit damage against stunned opponents
70% shock resistance and increased energy resistance
Heavy attacks give 85% chance to stagger for 8 seconds
Special attacks 100% apply shock and attacking a shocked opponent has 21% chance to stun them
Notable synergies:
Silver Centurion lets JF shocks last 25% longer
Mangog gives increased attack (6%)
Cap IW lets her deal 30% of her attack when nullifying a buff
and other, less important synergies
Joe Fixit:
Has the chance to gain two poker suits 50-95% of the time when one is rolled
poison immune
Starting the fight or after a heavy attack, he gets 1 poker suit:
spades - each attack has 14% chance to weaken or fatigue the opponent
hearts - regeneration ~12% per minute
clubs - increased crit rate per combo meter
diamonds - gains up to ~30% attack based on lost health
Sp1 and 3 can inflict bleed
Sp2 can stun
Notable synergies:
Hulk gives 6% attack
Kingpin gives him 20% attack if the opponent has any debuffs
Hood gives armor rating, crit rating, perfect block chance, and 5% health
Sorcerer supreme gives increased stun duration
Platpool gets Mode Mixer card selectivity
YJ gives villians 10% attack rating
and other, lesser synergies
Kamala Khan
Increased fury duration (2-8 sec) and potency (10%)
Increased block proficiency per fury active
Poison immune
Special attacks nullify 2 buffs if you have 3+ furies
Heavy attacks give up to 3 furies giving + ~5% attack each
Sp1 gives up to 4 furies for a total of ~60% attack increase
Sp2 gives 1 fury of + ~39% attack
Sp3 has 90% chance to give a ~39% permanent fury. All other furies last at least 10 seconds
Notable synergies:
Other Ms. Marvels give Increased health and attack
Spidey SE gives +30% fury potency
Nick Fury while alive gives all champs +20% fury duration
Black bolt gives cosmic champs increase buff duration for fury, armor up, precision, and cruelty
Captain Marvel gives 20% chance to armor break on all attacks per stack of fury
Guillotine
Chance to health steal for 20-55% damage done, which can be increased with ancestor souls
Increased armor rating, and increased crit damage per soul
Crits give 50% chance to bleed
Sp2 consumes 2 souls to reverse healing for 10 seconds
Sp3 consumes all souls to deal 2% of the opponents health in damage per soul
Notable synergies:
Venom gives 6% attack
Magik gives crit rating and perfect block chance
Stryfe increases soul duration by 30% and pauses during specials
Night Thrasher gives increased crit damage per soul
Heimdall gives all champs the dash-back-precision buff
Gamora gives 50% chance to gain a soul when striking a bleeding opponent
Ronin gives 30% chance to gain a soul every 4th light attack
Morningstar gives +10 second soul duration
Guilly 2099 gives +20% bleed ability accuracy and potency