Thanks for picking an interest in this great game mode. We always need more and better Arena players to improve the quality and diversity of the experience for everyone. If your video can attract even a few players to the Arena on a regular basis, then it’s worth making.
Having said that, here comes my feedback. Please don’t take any offense from it, I’m doing my best to be constructive, here. ^^
First of all, I’d recommend making sure you’re fully awake and perhaps making an outline of what you want to say before hitting the record button. Ironically, you mention at some point that you hate YT videos that drag on and on, but you’ve made a 19 minute video… that’s super long just to give a few basic tips!
There’s a lot of repetition, hesitation and other moments that could easily be cut off to improve the final result. You could give the same amount of info in 2-3 minutes, honestly, maybe 5 if you want to include an entire fight as a bonus demonstration (but in that case, you might want to give the tips at the beginning, all at once) and I think it’d be a lot better for it.
Secondly, don’t take this the wrong way, but the fact that you obviously play Arena and like it enough to want to make a guide about it, but were yourself still unaware of some of the fundamentals such as Traits being negated speaks volumes of Arena awareness in general.
If your guild mates didn’t know you can change your Hero’s weapon, close the Arena in between fights and resume your run later, or rearrange your line-up’s positions between fights (you can also change your weapon in between fights, by the way) or other basic functions of the game mode, then we really might need a basic tutorial in game.
I always assumed that people picked up this kind of info after their first run or so, just by seeing their opponents’ line-ups. But to be fair, there’s a LOT of line-ups that make no sense out there. I keep seeing stuff like the Hero at the top with Prismatic Orb or Imperial Jewel, or entire line-ups with color overlap, like they expect to get a team bonus as in constructed, and that’s just sad. The meta is basically divided between these noob line-ups and hardcore Arena players who make sensible picks, focus on the most currently powerful troops and weapons, and arrange their line-ups accordingly. There’s not much middle ground between these two extremes.
Last but not least, you mention the Retire button as a thing. That is not a thing. Let’s not encourage bad drafters to believe in the unplayable draft myth. You should never retire an Arena run. You have nothing to lose by playing it out and, more importantly, if you really end up with a team that does no damage at all, or otherwise sucks, you should take this as an opportunity to learn from your mistakes and draft more wisely next time. Not blame it on bad luck, retire the run, and then apply the same poor drafting technique to your next run. That would be my advice to people who use or even consider using the Retire button.
Other than that, you give sound tips and I would have made a fairly similar draft to yours given the picks in your example. I would have picked a different weapon, probably St Astra (but you don’t seem to have it) and switched the Wight and Grave Knight around (Wight is super weak to true damage early on, wherever you put him, but he can tank up a lot after a few spell uses; Grave Knight is far less useful in the late game and if you lose your Hero at some point, 7 attack is better than 6 on your top troop).
In any case, I would strongly suggest this timeless guide as a starting point for anyone interested in getting into the Arena and/or brushing up on their fundamentals:
The last update was a few patches ago, but there hasn’t been a major revolution in how the Arena works since then (not a permanent one anyway).