I didn't see anyone actually posting a serious opinion on this topic, and didn't see ESEA changing it's whitelist since S15 so I thought i'd give a shot in expressing my thoughts and sharing it with you guys.
I know this thread is not really serious and not really meaningful in anyway but i'm going to try and to give a serious opinion on this whitelist issue since there are so many weapons in the ESEA whitelist that even ETF2L allows that really don't change the meta too much and can be viable alternatives.
I also know how much you guys are tired of Euros coming here and talking 'bout ESEA and comparing it to ETF2L but i'm not here to do that, i'm merely here to give my opinion on some unlocks that should be considered.
ESEA whitelist vs ETF2L whitelist (which is going to be used in s20 most likely)
Scout: Both whitelist are the same.
Soldier: On this one ETF2L is a bit ahead with the primaries however behind with the secondary and melee weapons, so let's take a look at the primaries that are should be considered to be allowed in ESEA:
Cow Mangler and Liberty Launcher - both unlocks are being tested for about the past 2 weeks on TF2Pickup and both are quite interesting unlocks and can freshen up the whitelist however they won't see too much use in the regular season I believe.
The Cow Mangler's infine ammo and 5 4 shots seem to be on par with the slower reload (edit: only on the first reloaded shot) which can really hurt the soldier so it might be considered to do so.
The Liberty Launcher's less damage can get really frustrating however with it's faster projectile speed it seems to balance out the weapon and might be a viable option alternative.
Pyro: ETF2L is behind on this one with banning the Manmelter for some reason(?), so nothing much to be considered here.
Demoman: ETF2L is way behind on this one, so ESEA is good for this one, I don't know too much about the new Demoman unlocks, which both have downsides and upsides and can both be used wisely, however nothing much have been seen from these two, I'd love to see them tested somewhere so we can know a little bout them.
Quickiebomb Launcher - 2 less stickies in clip, can destroy stickies (broken, it can't for some reason), detonates faster however the sticky disappears after 2 seconds so that would mean no sticky traps, also has faster charge speed. Seems balanced however I'm not sure how many demos would give up sticky traps for this, could be worth a shot.
Iron Bomber - this one seems pretty weak and not overpowered at all or would be too gimicky to play against so I think this deserves a shot and maybe considered.
Heavy: ETF2L seems to be ahead in the primaries and secondaries however behind in the melee weapons, ESEA should consider the following weapons to be unbanned:
Huo-Long Heater and Tomislav - both weapons are somewhat weaker and better than the stock minigun which seems to be the only thing allowed for some reason, both can be used in some situations and none are overpowered or should be considered broken, both played very well in the last season of ETF2L and should be considered as viable options.
Dalokhs Bar - was banned for some reason after S14 but it shouldn't have since it gives a small buff to the heavy that doesn't change too much of the way the heavy plays, and also helps heavy survive just a bit more in defending. Allowed in ETF2L and was played fine in last season.
Engineer: When I took a look at the Whitelist ESEA has for the class I was shocked of it's limitations of just 1 allowed weapon(!), which ETF2L is way ahead on this one and has shown that the Engie deserves some love and has some unlocks that aren't totally overpowered or a straight up upgrade and ESEA should consider unbanning:
Frontier Jutice and Widowmaker - Both unlocks are allowed in ETF2L and don't change the meta too much, but actually are viable options for the primary shotgun.
The Widowmaker is a risky weapon that rewards hitting your shots, so if you miss them you'll be left without a primary weapon and without metal which seems very balanced to me, and also played fine in the last ETF2L season.
The Frontier Justice is quite risky aswell and isn't a straight upgrade or overpowered, it rewards getting kills with your sentry, however it will be vary rarely happen that you would get a kill, destroy your gun and still play Engie and get a crit to be actually used, so the weapon deserves to be unbanned or atleast considered.
Southern Hospitality and Eureka Effect - Only the Southern Hospitality is allowed in ETF2L but the Eureka effect should be totally considered to be allowed in both leagues, and seem like viable alternatives to the Engie's available melee weapons.
Southern Hospitality was banned after S14 for some reason, however it shouldn't have been banned because it is not an overpowered weapon nor is broken in any way, played well in the last ETF2L season aswell, so it should be considered back in.
Eurkea Effect was never considered however after the recent nerf it seems really underpowered and can be used to make some interesting plays with the new mechanic it got, doesn't seem overpowered nor broken therefore should be considered to be unbanned.
Medic: ESEA is ahead of ETF2L on this one, and it seems great.
Sniper: ESEA is ahead of ETF2L on this one aswell, and it seems great.
Spy: ESEA is ahead on this one aswell, and it seems great.
That's about it, the ESEA whielist didn't change at all since S15 according to Whitelist.tf so it seems like it could use to freshen up a bit, the whitelist won't harm itself by unbanning some weapons that don't really deserve to be banned.
Hopefully we will see the best league in TF2 keep on going and going strong.