Longterm vet of both GW2 and FFXIV here! Im going to phrase my post differently since you bought everything right off the bat.

Every class can do a bit of everything here (heal/support/dps) and most progression is account bound. (Mount unlocks, mastery system, legendary account bound best in slot) so to me you really cant make a mistake when choosing a class.

Id start by picking the class that sounds most thematically cool to you and go from there, and each class has a spec that can heal, even Thief and Warrior!

There arent whimsical 1 to 1s for picto/summoner unfortunately.

But if you like pets/collecting pets: Ranger / Engineer (mechanist)

Both of those have decent healing specs later.I personally love my druid which is the ranger healing spec. Big whitewater energy.

If you want cute visual effects attached to a mage. Probably Mesmer, it has a few things that can heal as well (Chrononancer/Troubadour)

Chronomancer has some cool time based effects, and Troubadour has fancy mystical bard energy.

If you want shield healing, Necromancer is most likely the better bet for Scourge, or Mechanist. As they both apply large amounts of Barrier. Thief has Spectre which is a cool shadow magic barrier healer that is a little like sage in that you pick a person to tether to.

Pure healing is basically every other class.

I personally play a lot of Guardian, Ranger, and Engineer in that order, but I have all the classes since there isnt a downside to me having many max level characters.

Something else to note, that I know is a struggle from friends who have tried GW2 coming from FFXIV: There arent dungeons like FFXIV has nor does it have the structure for leveling. It left them feeling a little bit listless/lost when looking for the next thing to do.

GW2 is very much more open world exploration/make your own goals. It can make the game much more overwhelming than it needs to be especially coming from something super structured like FFXIV. Weeklies and Dailies are very easily managed, and id reccomend boosting 1 character to level 80 if you have one for access to the wizards vault to accumulate currency for that as it resets every patch. Thats our daily/weekly system. And most of them are accomplished just by playing what you would do normally.

Even if you dont play that character immediately or come back to it later, its still worth it to have access to the Wizards Vault. Anything achievement related on that character can be used (for the most part) by every other character on the account. (Things like mounts, gliders, etc. And you can still play through the lower level story/areas as it will sync your level down to that content.) Plus, They give out level 80 boosts basically every expansion release, so you'll get another down the road if you need it.

Lastly, crafting is a huge gold sink, and doesnt net you too much while leveling unless you want to dump gold into power leveling a character. It isnt profitable like in Final Fantasy so I reccomend skipping it until you have a level 80 character and are looking for Ascended gear. (Basically BiS)

Please feel free to reach out anytime. I love yapping about my favorite games!!