1) There is fail stacking, but nowhere near as gruesome as games like BDO utilize. And it's transparent. You actually get to see the percentage chance listed before you pull the trigger. As well, it's transparent how to increasea your chances. ie.. You'll not only see your base chance percentage, but you'll also see how the mats you're using boost that chance. It's much more forgiving compared to other MMO's.
2) You can boost your gear from the outset. But realistically you really don't need to until you level cap since you'll quickly outgrow the earlier gear quickly. You can find/craft/buy better stuff along the way to level cap. Boosting your gear before level 45 is a waste.
3) Never paid much attention to the fees. They're insignificant enough that I really don't concern myelf with it compared to other games where it's a big issue. The market automatically chooses the max/min prices you can list. Taking into account the current stock of items you're trying to sell (sometimes the min price is bumped up because there are too many items listed lower, so bumps the min listing price so that it's never stuck perpetually at a low price).
4) Professions are 2 categories and each character/toon gets to choose 1 from each category. Main professions are Armorsmith, Echantment, and Handiwork. Sub/Secondary professions are Cooking/Alchemy. They're extremely useful. As for profitable... somewhat, but not extremely so. A dedicated lifeskiller toon isn't going to get rich.
5) I wouldn't consider Taming a lifeskill, as everybody gets it by default, and there's no selling your pets/mounts (that I've seen anyway). Aside from taming, those I listed in #4 are the only lifeskills.
6) Nope, no trading like you are probably referring to in BDO.
7) It's not pay to win. Despite what some people claim. At worst, it could be called Pay to Progress Faster. That's about it. And even then, you can earn cash shop currency just by playing the game and not have to pay cash.