I always try to be mindful of that and discuss stuff only from the perspective of what we have already seen on the show. Sometimes it is hard to block out future events.
I don't see any potential spoilers on that list though, but I think #2 is what you might think to be spoilerish. It really isn't though, the show just doesn't really have time to get into character-backstory and world building.
But looking at the list, that shyt is wack as fukk. "Do you actually read books or just skim through em" - Jay-Z to whoever wrote that list
1. Ser Arthur Dayne -- Yes
2. Omitted due to possible spoiler -- No fukking way, dude doesn't even use swords as far as I know
3. Jaime Lannister -- Top 10 maybe, but no way #3. Barristan in his prime would have mopped the floor with him.
4. Barristan Selmy -- Yes
5. The Hound -- In the discussion, but not above his brother The Mountain. Similar skillsets but The Mountain is much bigger and stronger
6. Syrio Forel -- Based on what? They are really reaching with this one here. There is nothing that indicates that Syrio is even a top 10 swordsman in Braavos, let alone the entire world
7. The Mountain -- Yes, probably needs to be higher
8. Bronn --
.....a great sellsword, yes, but cmon. Once again, nothing to indicate he deserves to be this high. Maybe a top 10 currently alive in Westeros, but even that would be a tough sell
9. Robert Baratheon -- Hell no, dude didn't even use a sword he used a warhammer. His skill was in large melee's, where he could overpower and overwhelm with brute strength. Beating Rhaegar doesn't make him top 10
10. The Blackfish -- I must be missing something because I see nothing to indicate he should even be in the discussion
Notably missing from the list:
Khal Drago -- A fukking beast 1 on 1, in a no armor fight he might be top 5. Tough to say how he would fare against someone with armor. He counts as a swordsman because the Dothraki
Arkah (spelling?) weapons are supposed to be longswords with a curved end
Numerous Kingsguard -- The kingsguard throughout history certainly has better swordsman than some on this list
The Smiling Knight -- Was the "Mountain of his time" only even meaner. Was better than a young Jaime Lannister but tough to say how he would fare against a prime Jaime
at Jon Snow.....I'm a Stark stan but damn that is some dedicated fanboy shyt
