Essence Font should only be used to get the HoT effect out in order to quickly burst single targets through the double Gust of Mist hits. Cancelling a cast of it when your party has the HoT effect rolling on all of them will allow you to use Mastery-proccing spells faster for burst healing on any target that needs it. However, continuing the channel can be the right call in specific situations, normally when you need group healing while you yourself are moving. It depends on the situation at hand.
It’s a good thing that the previous expansion, Legion, was the best in the game’s history because Battle for Azeroth is coasting on its success. The major class redesigns that happened then remain in effect (though some are a little worse, and some a little better), and the combination of World Quests and Mythic+ dungeons means there’s always something to do, no matter your skill level or how long you can play.
If you queue as a healer - take care to always have a stack of water of appropriate level. You can buy it at an innkeeper for next to nothing, but remember that it will become too low-lvl for you very fast, so you need to buy new water every 10-20 levels. Alternatively, you can buy a stack of every tier of water in Stormwind, and just always carry it with you. Another alternative, if you see a mage - always ask him (politely) to create a table for you. Grab 2-3 stacks so you have extra for the next runs.
The prepatch for Battle for Azeroth first hit on July 17th, but the first real pieces of story weren't available until this week (more on that in a minute). The storyline is called the War of the Thorns, and it's intended to hype up the faction-vs.-faction conflict that makes up the core of BfA. Instead, it feels like it's sucking the air out of the room.
Allied races aren’t much better. You can only earn them by grinding out reputation. It doesn’t take that long but casual players will need to invest a couple weeks primarily to it, and focusing on that grind will take you away from others, like earning gear. Each race has its own grind, but the things you do to work through it remain the same, adding to your boredom.
The prepatch is just a patch, at the end of the day. The expansion is yet to come. But this significant stumble causes me to pause and contemplate what we're getting when BfA hits. Will AI-infused Islands and massive PvE Warfronts represent enough new gameplay? Or will the new zones just feel like an in-game content patch (Argus, say, for Legion players) on steroids?
If you love running old content for transmog items, you'll love the new legacy loot system. Whenever a player enters a dungeon or raid where they are 10 or more levels above the content, the dungeon or raid bosses drop an amount of loot equivalent to what would have dropped for a full group when the content was current. That means players could earn loot for five people in dungeons and loot for 20 people after soloing a raid. The legacy loot system also drops other gear types, like cloth dropping for a plate wearer. It's now much easier to get the transmog gear you want, and you can also collect gear for your alts on the same run.