No queueing here when I tested it out for 15 minutes. I'm guessing traffic has died down a bit. No way I was going to bother logging in at launch time as it was 2 AM here.
NightSicarius
Mana was slow for me up until around level 50 when I started getting sacred gear with better stats. Get some increased lucky hit chance, get some "mana on lucky hit", add in skills like Avalanche and the aspect that doubles it, aspect to recover mana when you use a cooldown, etc.
It all starts to add up. Lucky hit is a big one with ice shards (with piercing aspect) because it hits so many enemies. As long as there's a big group, I now never have mana issues. It's only in one-on-one fights that I'll run out of mana, but then I can teleport / frost nova / frost armour / flame shield to regain mana.
Finishing the campaign unlocks the campaign skip for new characters. Seasonal characters will not be able to access seasonal content (malignant hearts, extra story, etc) until the campaign is complete or skipped... so unless you feel like playing through the whole campaign again, you'll want to complete it with your eternal character first.
My sorcerer using ice shards / frost nova at level 70 was still blasting through everything. I hadn't even bothered levelling paragon glyphs or anything, so I imagine it'd be even better if I did.
But I spent the last week or two playing as a barbarian to level 65 and it was just so much fun smashing everything.
I probably won't play until the weekend, then will make a start on season character. I'm thinking I'll go rogue as I haven't even tried that class yet.
Bonus points if you wait for the quest dungeon to pop up as a Whispers dungeon. Extra extra bonus points if you wait for it to be a Whispers dungeon and then activate a nightmare sigil on it.